Hair
CINEMA 4D Programming Team: Christian Losch, Philip Losch, Richard Kurz, Tilo Kühn, Thomas Kunert, David O’Reilly, Cathleen Poppe. Plugin Programming: Sven Behne, Wilfried Behne, Michael Breitzke, Kiril Dinev, Per-Anders Edwards, David Farmer, Jamie Halmick, Richard Hintzenstern, Jan Eric Hoffmann, Eduardo Olivares, Nina Ivanova, Markus Jakubietz, Eric Sommerlade, Hendrik Steffen, Jens Uhlig, Michael Welter, Thomas Zeier.
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Contents 1. First Steps ........................................................................................................ 11 How can I let Meg’s hair grow? ........................................................................................................... 11 Grass, Fur, and More....................................................................................................................... 13 Guides, Hair Materials and Hair ...............................................................
Invert .............................................................................................................................................. 24 Grow Selection ............................................................................................................................... 24 Neighbors ....................................................................................................................................... 24 Distance .......................................................
Scale .................................................................................................................................................... 73 Frizz ..................................................................................................................................................... 74 Kink...................................................................................................................................................... 77 Density..............................
Forces Tab .......................................................................................................................................... 188 Cache Tab .......................................................................................................................................... 188 Advanced Tab .................................................................................................................................... 189 6. Render Settings....................................
1 First Steps
First Steps • 11 First Steps How can I let Meg’s hair grow? The following mini tutorial only serves to quickly demonstrate how Hair works. Hair is very versatile and offers numerous possibilities for achieving the look you want. 1. Load Meg into your scene (Object Manager: File / Load Object Preset / Humans / Meg). If you want, you can delete everything except her head. 2. Switch to the Use Polygon Tool and select the polygons on which the hair should grow.
• First Steps Select “Set as Dynamics” in the main Hair menu to fix the guides at any given state. How you continue to style the hair is entirely up to you. You can manipulate all guides using the Hair tools (see chapter 2). An excellent tool for this is the Brush Tool, which can be used to brush the guides interactively in the editor view. You can reduce the number of guides. You can select and manipulate individual guides.
First Steps • 13 The length of the rendered hair is reduced additionally by the “Frizz” material channel. The “Clump” channel was also applied. Grass, Fur and More Another common use for Hair is to cover a vast surface with hair, without the use of guides (guides are present internally but cannot be edited). The look of hair applied in this fashion is primarily determined by the Hair material settings. Follow these steps if you want to create a grass-covered surface: 1.
• First Steps A (Hair)Render Tag (see chapter 5) can also be applied to the hair-covered object, which will broaden the influence you can have on the hair. Hair count, length and the dispersion of hair (using the Polygon Selection Tag) can be edited. Note: Such hair will, by default, be rendered as fill hair (see chapter 4), to which certain restrictions apply. Guides, Hair Materials and Hair The guides may give the impression that they define where hair will grow, but that’s not the case.
First Steps • 15 If guides and hair are viewed as layers, the “Fill Hairs” can be considered a sub-layer (Hair Object: “Fill Hairs” tab). Fill hairs are interpolated by and between hairs. Fill hairs are especially useful for creating fur or carpets - such surfaces require very dense coverage, and fill hairs require less memory for rendering.
2 Tools, Functions, Modes
Tools, Functions, Modes • 17 Tools, Functions, Modes General All of the tools, functions and modes described in this chapter can be found in the main menu under “Hair”. Tools The numerous Hair tools are designed to manipulate (style) the guide so you can style hair any way you want. Guides determine the direction and length of the hair (hair style). Hair is interpolated between the guides, and can be seen when the image is rendered.
• Tools, Functions, Modes Using “Add Hair” to create guides / hair will generate guides on each point of the object. These guides can be edited using the tools described in this chapter. In addition to being affected by guides, the rendered hair is also affected mainly by the Hair material (chapter 3) and the Hair object (chapter 4). Feather Object See chapter 5 Modes Guide Modes Modes from left to right: guide, Points, Tips, Vertex, Root.
Tools, Functions, Modes • 19 Edit Cut Guide “Cut Guide” performs the same function as “Delete Guide” (deletes all selected or partially selected guides), with the exception that the deleted guides will not be cached. Copy Guides Use this option to copy selected guides. These can then be pasted with the next option (“Paste Guide” ). This makes it possible to copy guides from one Hair object onto another. Paste Guides Use this option to past guides copied using “Copy Guide”.
• Tools, Functions, Modes Convert From Spline Use this option to convert a selected spline (not Spline Primitives!) to guides. A guide will be created around each spline segment. This option’s primary purpose is to convert hair imported into CINEMA 4D from other applications as splines to guides. Normally, Hair uses relatively few spline points when creating guides. Since guide segments are created practically equal in length, guides can differ quite a bit from the splines.
Tools, Functions, Modes • 21 Hairs to Guides Use this option to convert any and all hair to be rendered (Hair object: “Hairs” tab / “Count” ) to guides. New guides will be interpolated between existing guides. Hair materials will not be evaluated. The distribution of hair will automatically be set to “As Guides” in the “Hairs” tab. Unroot Guides Use this option to unroot all selected or partially selected guides. The pros and cons of this are explained in chapter 4, “Unroot guide”.
• Tools, Functions, Modes Select Locked If this setting is active, locked guides can be selected as well. Shape A small sampling of possible tool shapes (“Aspect” and “Angle” values were varied). Use “Shape” to define the shape of the tool: “Circle”, “Box” or “Diamond”. Aspect Use this setting to stretch the shape of the tool in a horizontal direction. Pressure If you use a graphics tablet, use this setting to define which settings will be affected by the pressure of the pen.
Tools, Functions, Modes • 23 Select Hidden Use this tool to select guides or guide elements that are hidden by a hair-covered object. If, for example, you create hair on a sphere, the hair on the opposite side of the sphere will also be selected. Selection Use this tool to select specific guide types or their points.
• Tools, Functions, Modes Select All Selects all guides or guide elements (depending on the mode selected) of the active Hair objects. Deselect All Deselects all guides or guide elements (depending on the mode selected) of the active Hair objects. Invert Inverts the active selection. Grow Selection Use this tool to expand the selection to neighboring guides or guide point selections.
Tools, Functions, Modes • 25 Hide Use this tool to hide all selected or partially selected guides. Select “Show All” (see below) to unhide guides. Hidden guides will not be affected by the Hair tools. The Hair dynamics will, though, continue to affect the hidden guides. Hide Locked Use this tool to hide all locked guides. Select “Show All” to unhide all guides. Show All Use this tool to unhide all hidden guides. Lock Selected Use this tool to protect selected guides from being edited inadvertently.
• Tools, Functions, Modes Unlock Selected Unlocks selected guides. You can select locked guides by activating “Select Locked” for the given selection tool. Set Selection This tool lets you save any guide or guide element selection to a Selection Tag. You can then access the saved selection at any time, just like you’re accustomed to doing with normal CINEMA 4D Selection Tags. There is, though, one small difference: Each mode will not be given its own Tag. Instead, the mode will be saved with the Tag.
Tools, Functions, Modes • 27 Tip: Switch to the “Root” mode if you want to move complete guides without altering them. The guides must first be released from the surface with the “Unroot Guides” option. Scale Scales the selected guides (exception: The spacing between points can be scaled in the “Point” mode. The “Relative” setting must also be active). “Scale” can be adjusted in the editor view or using the mouse.
• Tools, Functions, Modes Pivot Use this option to define the rotational axis: Root: Guide root segment. Cursor: Angle of view of the camera where the cursor is clicked. Hair IK Activate this setting if those guide elements being rotated should affect neighboring guide points that are not selected but belong to the same guide (the distance between guide points remains for the most part the same).
Tools, Functions, Modes • 29 Selected Only If this setting is active, only selected elements will be affected (guides, points, tips, vertices, roots). Hair IK If this setting is activated, a link will be established between the guide points. The distance between individual points will remain the same. If you move a point, the other points will follow. If this setting is not active, the points can be moved independently, without affecting others (just like moving CINEMA 4D spline points).
• Tools, Functions, Modes From left to right: “Move”, “Repel”, “Kink”. Fall-off These options define a given tool’s falloff from the center of the tool to the “Radius”. A visual depiction of Falloff can be found in chapter 10 of your CINEMA 4D reference manual. The “Spline” option lets you define your own falloff curve. Strength Use this slider to define the strength with which the brush tool should work. A value of less than 100% is recommended, which will give you better control of the brush effect.
Tools, Functions, Modes • 31 Distance Tab Activate the “Distance Fall-off” setting if you want the strength of the brush tool to abate along the length of the brush stroke. Distance This is the distance in screen pixels over which the falloff (or the abatement defined with the “Distance” “Fall-off” graph) will occur within a given brush stroke Fall-off Curve The guides pictured above are influence by the “Distance” curve below (“Kink” mode).
• Tools, Functions, Modes View Angle Tab This tab contains settings that will make the strength of the brush stroke dependent on the angle of the guide root segment. The default linear graph will cause the brush stroke to have its strongest effect on the guides whose root segments point directly towards the camera. The strength of the brush stroke will abate more and more as it moves in the direction of the root segments that point away from the camera.
Tools, Functions, Modes • 33 Comb Use “Comb” to comb guides in specific directions. The following settings are available: Direction As the name suggests, this setting is used to select the direction in which the guides should be laid. You can select from the following options: Camera X/Y/Z: In the editor view, the hair will bend to the right (X), downwards (Y) or to the rear (Z) (away from the camera).
• Tools, Functions, Modes Spline A simple circular spline over the surface of the head will create a twirl (inset). A spline object can be dragged into this field that will more or less determine the orientation of the guides. The following applies: The tangents of the splines nearest the guides will be used to determine the orientation of the guides.
Tools, Functions, Modes • 35 Geometry Weighting Top: A hair-covered Sweep NURBS; Below: The same curve after being combed using “Geometry Weighting”. The guides follow the shape of the geometry. “Geometry Weighting” is a very practical function to make guides follow the shape of geometry. Hair “looks ahead” a certain distance and will orient the hair based on the direction of the geometry. In the example above, you can see how the hair closely follows the shape of the curve.
• Tools, Functions, Modes Clump Use this tool to create Clumps with selected guides by “bending” the guides to their common center. Guides must be selected before applying this tool. A clump can also be twisted into itself. The strength can be regulated interactively by clicking and dragging the mouse in the editor window. Settings Towards From left to right: Selected guides; “Line” mode; “Center” mode; “Average” mode.
Tools, Functions, Modes • 37 Keep Lengths Deactivate this setting if you want the clumps to come together at one point. This will stretch (at 100% strength) guides located further away until they meet at a point. Otherwise, they will simply be attracted to their common center, but will not be stretched to reach it. Strength This setting defines how strongly the guides should be “clumped”.
• Tools, Functions, Modes Curl Use this tool to add spiral-shaped curls to selected guides. Two types of curls are possible: The guides will rotate in a spiral in the direction of the guide root (“Angle” and “Tightness” settings) Spirals will be created around the length of the guide (“X / Y Height” and “X / Y Length” settings). Pictured above are both curl types. The can, of course, be used in combination with each other. Left: “X / Y Height” = 0. Right: “Angle” = 0.
Tools, Functions, Modes • 39 Strength Use this setting to define the degree to which the hair should be curled. Negative values can also be entered, which will reverse the curl of the hair. Angle Left a small and large “Angle” value; right, a small and large “Tightness” value. “Angle” defines the amount of curl. Higher values will result in curls with an increased spiral. Tighten This setting defines the degree to which the curl should be bent in the direction of the guide root.
• Tools, Functions, Modes X / Y Length Use these settings to control how the “X Curl” and “Y Curl” curves will be applied along the length of the guides. Lower values will cause the curves to repeat more often. X / Y Curl Function Graphs (Curling Tab) These curves define the effect of the guide points on the individual guides. Both curves in their preset states, in conjunction with the correct phase distortion, will result in a perfect spiral.
Tools, Functions, Modes • 41 All settings from the “Radius” setting to the “Selected Only” setting function exactly as the “Live Selection” tool (see Live Selection, p.18). Length Enter here an absolute guide length to which the guides should be cut. Cut at / Apply Cut Object You can also cut guides using a polygonal object. Simply drag the object into the “Cut at” field and click on the “Apply Cut Object” button. All guides will be cut at their point of intersection with the object.
• Tools, Functions, Modes Top: The effect of the “Surface” setting. Bottom: The effect of the “Guides” setting. After adjusting the settings as desired, the “Apply” button must be pressed in order to apply the settings to the guides. Select Pushed All guides pushed by this tool will be subsequently selected. This is a good idea if you have just pushed some guides back over the surface. These guides will then be automatically selected and can be further edited.
Tools, Functions, Modes • 43 Distance This is the minimum distance to the surface that the guide points must maintain in order not to be pushed away. Entering large values here will not do any good since the guides will then only appear in a zigzag arrangement. Strength Use this setting to define the strength of push along the length of the guides. Guides When active, this setting serves to push the guides apart. This will only work well with guides containing few segments.
• Tools, Functions, Modes Direction Select the direction in which the guides should be made taut. Root: In the direction of the guide root segment. Normal: In the direction of the surface normals at the guide root. Along Guide: Over the length of an average guide. Extremely small kinks will be ironed out, whereby the run of the guides will, for the most part, remain unchanged. Strength This setting can also be adjusted interactively using the mouse.
Tools, Functions, Modes • 45 Count This is the maximum number of guides that will be set per individual click or each time guides are set (“Step” ). Length This setting defines the length of the guides that will be “painted” onto the surface. Min Spacing This is the minimum distance between set guides. Interpolated If this setting is active, newly created guides will be interpolated between existing guides.
• Tools, Functions, Modes Mode 1. Clone Cloned guide with “Auto Root” active. If in the “Clone” mode, the selected guides can be doubled and mirrored onto the opposite side of the mirror surface. 2. Interpolate This mode interpolates edited hairstyles. Guides must, though, already be present on the other side of the selected guides or of the mirror surface. These should be distributed symmetrically, since only very small diversions from “ideal” symmetry can be compensated for.
Tools, Functions, Modes • 47 Strength Use this slider to define the strength of interpolation on the guides. The higher the value, the closer the affected guides will match the mirrored guides. Search If the arrangement of guides is not perfectly symmetrical, when in the “Interpolate” mode, you can tryto find a fitting equivalent to the selected guides on the mirrored side by increasing the “Search” value (the guide root being the decisive factor).
• Tools, Functions, Modes Object If “Custom” is selected in the “Coords” setting, the coordinate system of the object placed into this field will define the coordinate system of the mirror plane. Set Roots Occasionally, it can happen that guides lose their link to the hair-covered surface (see chapter 4, “Unroot guide”). Use this tool to replant those guides. The guide roots will then be planted onto the nearest surface (of the object to which the Hair object is assigned).
Tools, Functions, Modes • 49 Symmetry Symmetrical brush stroke. Use “Symmetry” to style one side of the hairstyle - and watch how the other side is magically styled as well. You must, though, have a nearly symmetrical distribution of guides. The following settings are available in the Symmetry Manager: Symmetry: Use this setting to turn the symmetry effect on and off. This setting has the same effect as selecting “Symmetry” from the main menu.
• Tools, Functions, Modes Soft Selection Soft selection can be applied to all Hair selection tools, i.e. elements that lie outside a given tool’s radius will not be affected as strongly. The effect of a given tool will abate more, the further away an element is located from the tool. The weighted selections are shown in color in the editor view: Blue = not selected; red = selected.
Tools, Functions, Modes • 51 Coords Use this setting to define the dimension of the falloff radius: World: The positions of the guide points will be used. Screen: The guide points within a specified pixel radius will be selected. Radius This is the distance from the selection within which the falloff will have an effect. If a value of “0” is entered, a hard selection will be made, i.e. only those guide elements within the radius of the selection tool will be selected.
• Tools, Functions, Modes Dynamics Interaction This setting allows the effects dynamics (or parts thereof) on the hair to be seen without having to play the animation. Pressing the “Play Forwards / Backwards” buttons is then not necessary to see the effect of dynamics on the hair. Redraw Activate this option if you want to activate the interaction. Time Use this setting to define the intervals at which the depictions should take place in the editor view.
Tools, Functions, Modes • 53 You can, for example, simply drag a sphere containing a Collision Tag through the guides in the editor view (the “Dynamics” setting was deactivated in the example above). Activating the “Collisions” setting ensures that a collision will take place between the guides and the sphere. The guides will be bent accordingly.
3 Hair Material
Hair Material • 55 Hair Material General The Material Editor Just as with other materials in CINEMA 4D, the Hair material can also be edited in either the Material Editor window (double-click on the Hair material) or in the Attribute Manager. The Material Editor is used for the following descriptions and screenshots. A Hair material is made up of numerous material channels.
• Hair Material The Hair material can also be applied manually to the following types of objects: Hair‘s own Feather object (see chapter 5). Geometry, i.e. primitives such as cubes, spheres, etc. and polygonal objects. The Hair material will then behave like fur. The amount of hair and length is then adjusted using the Render Tag (see chapter 5). Splines: These will then be treated as individual hairs. Emitters: The particles will be treated as individual hairs.
Hair Material • 57 This applies only to the channels listed above and not to other channels. Is the order in which the above channels are applied important? Well, it’s similar to the CINEMA 4D Deformation objects – a different sequence would lead to a different result. Although this sequence cannot be changed, there is a trick you can use to work around this, if necessary: Let’s say you decide you want to apply “Frizz” before “Bend” is applied.
• Hair Material 2. Textures In this example, the Hair material channel “Kink” is defined using a texture. Most channels can also be controlled over an entire surface using a texture (vertex maps can even be painted!). Such a texture is always assigned to a setting that defines a maximum value that can be applied. In most cases, only the a shader’s or bitmap’s grayscale will be used.
Hair Material • 59 Channels The Color Channel Color The gradient (insert) was applied to the strand of hair. This gradient defines the color of the hair along the entire length of the hair. The left end of the gradient represents the hair root, the right the tip. Brightness Use this setting to adjust the overall brightness. A value of “0” results in black hair. As is the case with many other parameters, “Brightness” can be manually set to a value greater than the maximum of 100% set by the slider.
• Hair Material Blend If you want to texture hairs using a texture you have loaded, use this setting to define how the texture color will be blended with the hair color. All blend modes are described later in this chapter, under “Blend Modes”. This particular menu is available in many channels into which textures can be loaded and mixed with existing colors. Mix Use this setting to define the degree to which a texture that has been loaded should be mixed with the hair color.
Hair Material • 61 Tips The texture at the top right, was loaded into the “Tips” channel’s “Texture” field. If the “As Roots” option is active, the tips of the hair will assume the color of the roots. If you want to use a different texture for the tips, deactivate this option and load the desired texture into the “Tips” channel. The color(s) between the root and tip will then be interpolated along the length of the hair.
• Hair Material Surface The “Surface” settings are specially designed for rendering fur. “Surface” uses hair color, illumination and, if applicable, cast shadows to generate a fitting color for the fur. These settings (described below) will then be blended with the existing hair color. The “Additive” blend mode will blend the least. Surface Activate this setting if you want the object’s surface to assume the color of the hair. Color Left: “Color”, “Illumination” and “Shadows” active.
Hair Material • 63 Backlit Color In this example, one light source was placed in front of the hair, another behind the hair. Color in the “Color” channel was set to red, color in the “Backlit Color” channel was set to blue. This channel is responsible for coloring hair, when lit, that lies behind other hair. These settings are exactly the same as in the “Color” channel, with only two exceptions (explained below).
• Hair Material Mix The “Mix” setting lets you define to what degree the backlit color should be mixed with the color of the hair (“Color” channel). Example: A white backlight color was selected to brighten the hair that is lit from behind. Specular This channel primarily defines specular highlights. As in reality, rendered hair also has 2 sources of specular highlights. The first source originates from reflections on individual hairs, the second from an overall reflection from within the hair.
Hair Material • 65 Left: Both specular highlights. Center: Primary highlight only. Right: Secondary highlight only. Color In this example, a blue specular highlight was used. If you want to change the color of the primary specular highlight, this is where you do it. The color of the secondary specular highlight is determined by the hair color (“Color” channel). If you want to define the specular highlight color using a texture, simply load a texture into the “Texture” field.
• Hair Material Sharpness Increasing “Sharpness” values from left to right. The “Sharpness” slider controls the spread of the specular highlight. Tip: You can enter a value greater than 100% for most “Specular” settings. Setting “Strength” and “Sharpness” to greater than 100% can be especially helpful in achieving really “snappy” specular highlights. You can also get sharper specular highlights by deactivating “Vertex Sampling” in the Render Settings menu (Effects / Hair Render / Render Tab).
Hair Material • 67 Second set of parameters – Strength / Sharpness / Texture These are the settings for the secondary specular highlight. These settings behave just like the ones just described for the primary specular highlight. Below, the difference between the two is demonstrated: Left: Both specular highlights are active. Center: The primary specular highlight has been turned off. Right: Both specular highlights have been turned off.
• Hair Material A comparison of different transparency gradients. Use this channel to define the transparency of the hair. Transparency If the left end of the gradient represents the root and the right the tip of the hair, the grayscale will be applied as follows: Black = no transparency White = completely transparent Gray = transparency relative to the grayscale value You can also use transparency to simulate realistic backlighting (see “Backlit Color” ).
Hair Material • 69 Thickness This channel lets you define the thickness of the hair along its shaft. Usually, the narrower the hair, the more realistic it will look when rendered. The number of hairs rendered will have to be increased accordingly (Hair object: “Hair” Tab), which also increases render times. A good balance between the two will have to be found to achieve the best results. Tip: Often, hair effects can be better understood if you render just a few, maybe ten, thick hairs (e.g.
• Hair Material Very thick hairs are ideal for creating fiberglass light strands: Variation This setting varies the thickness of the hair root and tip by randomly adding to or subtracting from the values entered for “Root” and “Tip”. Curve This function graph lets you define the shape of the hair along its entire length.
Hair Material • 71 Texture In the example above, a Voronoi shader was used to define the thickness of the hair (see insert). If you want “Thickness” to affect an entire surface using a grayscale texture, simply load your texture here. Length This setting defines the length of the hair, in percent along the guides.
• Hair Material Length From left to right, a part with “Length” values of 20%, 60% and 100%, respectively. Use the “Length” slider to define at which length the hair should be cut. This is exactly the setting you need if you want to animate hair growing. Style your hair as it should look in its final state and animate the “Length” setting from 0% to 100%, and the hair will grow. Make sure you turn off dynamics (Hair object: Dynamics / “Enable” option).
Hair Material • 73 Scale Don’t mix the “Scale” channel up with the “Length” channel. “Scale” scales the hair, including its form, and does not cut it off. Scale The part in the example above was rendered, from left to right, with “Scale” set to 40%, 70% and 100%, respectively. Variation Use “Variation” to define the maximum random variance in the scale of the hair. A value of 0% will scale all hairs equally.
• Hair Material Texture In the example above, a grayscale gradient was used to scale the hair. Frizz “Frizz” lets you add chaos to your hair (To be exact, an internal Noise filter is applied). With “Frizz” you can let your hair bend in any and all directions, even over the entire length of the hair.
Hair Material • 75 Frizz Left: A lower “Frizz” value. Right: A higher “Kink” value. Use the “Frizz” setting to define the strength of the frizz. The higher the value, the frizzier the hair will be. Variation Use this setting to vary the overall frizz of the hair. Scale X / Scale Y In the example above, the hair is viewed from above. The “Scale X” and “Scale Y” values from left to right: 10%, 100% and1000%. Use these two settings to adjust the chaotic structure of the hair.
• Hair Material Curve The curves pictured (insets) result in the frizzes shown. “Curve” lets you define precisely to what degree, along the length of the shaft of hair, “Frizz” should affect the hair. Texture A texture loaded here will use its grayscale values to define the amount of “Frizz”.
Hair Material • 77 Kink The “Kink” channel is similar to “Frizz”. It also uses an internal Noise filter to give the hair shaft a chaotic look. The “Kink” filter, though, roughly maintains the original shape of the shaft (“Frizz” can be used to completely change the shape of the hair shaft). Kink Left: A lower “Kink” value. Right: A higher “Kink” value. The “Kink” slider lets you define the strength of the “Kink”. The higher the value, the more kink the hair will have.
• Hair Material Scale X / Scale Y Viewed from above, the “Scale X / Scale Y” values are set to 10%, 100% and 1000% respectively. Use these two settings to define a chaotic change of direction of the hair. The greater the value, the more often the hair will be kinked. You can also enter values greater than 100%, if desired. Note: Make sure not to enter equal values for “Scale X” and “Scale Y”. This would lead to “Kink” being applied only on a single layer.
Hair Material • 79 Density Density Left: A lower Density value. Right: A higher Density value. The “Density” setting defines the overall density of the hair. This value directly affects the hair on a specific Hair object (Hair Tab), and defines how many of those hairs will be rendered. Density Levels This setting affects any texture that is loaded into the “Texture” field. If used, it will quantize the texture internally, based on its grayscale values.
• Hair Material Texture The density of the hair pictured above resulted from using the texture shown at the bottom left (insert). A bitmap or shader can be loaded here that will define the density of the hair based on its grayscale values. Clump With “Clump” you can create clumps of hair or shaggy hair. The “Clump” channel groups hair and automatically twists and twirls it.
Hair Material • 81 Count “Count” defines the maximum number of hairs that will serve as “central hairs”, around which a defined amount of surrounding hair will snuggle, thereby creating clumps of hair. For example, if you have 1000 individual hairs and want to create 5 clumps, you would enter a value of 0.5%. Clumps are randomly positioned onto hair roots. “Count” only defines the maximum number of possible clumps.
• Hair Material Tip: If you want the “Radius” setting to have priority, set higher values for “Count” and “Limit”. The creation of clumps will then done predominantly by the “Radius” setting. “Variation” causes a variation in the size of the clumps. The value entered here will be randomly subtracted or added. Twist / Variation From left to right: Increasing “Twist” values. Use “Twist” to define how the surrounding hair twists around the “central hair”.
Hair Material • 83 Include Roots Left: “Include Roots” not active. Right: “Include Roots” active. Activating this option will also cause the hair roots to change position, which will make the object’s surface visible between the clumps of hair. Be careful, though, this effect uproots the hair, which will lead to problems when using SPD ( Advanced Render module) and normal material displacement because the hair will then no longer be arranged correctly on the object’s surface.
• Hair Material Fall-Off Function Graph Use this function graph to adjust the clump strength (“Clump” setting at top) across an entire surface. Only the grayscale value of a colored texture will be utilized to affect the hair. Clump Texture Field A texture loaded into this field will affect the clump strength across an entire surface covered by that texture. Only the grayscale value of a colored texture will be utilized to affect the hair.
Hair Material • 85 Radius Texture Field A texture loaded into this field will affect the radius across an entire area, utilizing its grayscale values. Twist Function Graph The “Tighten” channel will amplify existing waves and curves, and straight hair will curl. This Hair channel analyses all existing waves and curves and amplifies them (negative “Tighten” values will “relax” the hair). Hair that is completely straight will be curled in the direction of the root.
• Hair Material Curve In the example above, “Tighten” was adjusted to make each hair curl in the center. Use this curve to define the tightness along the length of the hair. Texture A texture loaded into this field will affect the tighten strength across an entire area.
Hair Material • 87 You should already be familiar with the displacement channel in CINEMA 4D, which raises, lowers and displaces surface points using a texture. The Displacement channel in Hair basically works the same way: Hair points are displaced in 3D using the curves in the Displacement channel (“X Curve”, “Y Curve” and “Z Curve” ). These graphs can be used to precisely adjust the hair – as long as you’re not using guides.
• Hair Material Advanced Include Root If this option is active, “Displacement” can also be used to move the hair root. This will, though, uproot the hair and the hair will no longer be attached to the object surface. This will lead to problems when using SPD ( Advanced Render module) and normal material displacement because the hair will then no longer be arranged correctly on the object’s surface.
Hair Material • 89 A texture loaded into the “Direction” field will use its RGB values to define the direction of the “Displacement” effect. The RGB values affect the direction of the hair as follows: Red - X Green - Y Blue – Z RGB values can affect the direction of the hair in either a positive or negative direction. Color values up to 127 will have a negative effect, whereas color values greater than 127 will have a positive effect.
• Hair Material Bend / Variation Increasing “Bend” values from left to right. Use the “Bend” setting to define the amount each hair should be bent. The greater the value for “Bend”, the more the hair will curve (be bent). Very large values will cause the hair to assume a circular form. The “Variation” setting defines the degree to which the hair will randomly change its size. Amount Use this slider to define the percentage of hair that should be bent.
Hair Material • 91 A top-view onto an area of hair growth, influence by the texture shown at the lower left of the image (insert). Advanced From Root Top: “From Root” not active. Bottom: “From Root” active. Activating this option will take into account pre-existing bent hair, e.g. hair bent using guides (See top insert in the image above, where guides were used to bend the hair to the left at the tips), when the “Bend” channel is applied.
• Hair Material Strength Function Graph Various graphs and their effects. Use this function graph to define the curvature of the hair over its entire length. To set the hair to a neutral (straight) state, position the function graph horizontally in the center. Texture A texture can be loaded here, with which the curvature of the hair can be defined. Curl The “Curl” channel curls the hair by slightly rotating each segment of hair.
Hair Material • 93 Curl Increasing “Curl” values from left to right. “Curl” defines the degree to which the hair should be curled. The higher the value, the curlier the hair will be. A negative value will reverse the direction of the curl. Negative and positive “Curl” values in comparison. Of course, such curls can also be created using guide styles in the Hair Tools (e.g. the Curl Tool). Variation Use the “Variation” setting to adjust the irregularity of the curl.
• Hair Material Direction Use this setting to define which coordinate system should affect the hair. You can select from: World: World coordinate system (direction is determined using the “Axis” setting). Local: Object coordinate system (direction is determined using the “Axis” setting). Random: Each hair will curl in a random direction. Hair: The hair will curl in the direction already defined by guides for the hair curvature and waves.
Hair Material • 95 Curl Function Graph Use this function graph to define the strength of curl (“Curl” setting at top) along the entire length of the hair. Various graphs and their effect on the guides shown at the lower left. Texture A texture loaded here will define the strength of curl (“Curl” setting at top) across an entire surface. Twist The “Twist” channel twists and turns the hair around any axis.
• Hair Material Axis Axis settings, clockwise from top left: “Normal”, “Root” (root is blue), “Guide”. All examples use a guide to demonstrate the respective axes. Use this setting to define the rotational axis for each individual hair. The following options are available: Normal: Defines the center of rotation around which the entire hair should twist, using the surface normals at the root. Root: The hair root segment (the segment adjacent to the root) is designated as the rotational axis.
Hair Material • 97 Amount Use this slider to define the percentage of hair that should be twisted. Curve Function Graph Use this function graph to define the strength of twist along the entire length of the hair. Texture A texture loaded here will use its grayscale values to define the strength of twist across an entire surface. Waves The “Wave” channel uses real sin curves to affect the hair, this is why some settings are titled “Phase” and “Frequency”, for example.
• Hair Material X Scale / Y Scale Imagine the hair growing on the Z-axis: The “X Scale” and Y Scale” of the sine curve would affect the hair perpendicular to the Z-axis in both directions, respectively. Very large values for “X Scale” and “Y Scale” generally aren’t necessary. Amount Use this slider to define the percentage of hair that “Wave” should affect. Phase X / Phase Y From left to right, “Phase” values of 0°, 90° and 180°, respectively.
Hair Material • 99 Effect on Strands of Hair Left: Strand without “Wave” applied. Center: Two strands with “Wave” applied, but with different frequencies. Right: Strand with a high “Wave” value. Straighten You can “ruin” any hair style you’ve created, using the “Straighten” channel, regardless of whether it was created using guides or Hair channels: The hair will be straightened, either by aligning it to the normals, the guides or to the hair root segment.
• Hair Material Amount Use this slider to define the percentage of hair to be straightened. Strength / Variation Use this setting to define the strength with which the hair should be straightened. Use “Variation” to randomly vary the degree to which individual hairs will be straightened, within the settings of this channel. Curve Function Graph Use this function graph to define the strength with which the hair should be straightened over the entire length of the hair.
Hair Material • 101 Illumination Illumination Receive GI / Strength GI can be applied to hair if the “Raytrace” render mode has been selected in the Hair render presets’ “Render” tab ( Advanced Render module only), the quantity of which can be adjusted using the “Strength” setting. The hair itself will not use GI to affect other objects.
• Hair Material Diffuse Top: A very low “Diffuse” value. Bottom: Maximum “Diffuse” value. The effect of this setting remains very understated and can best be seen when the hair tangents run in the direction of the line of sight, e.g. when looking at a parting in hair from the top. Diffuse hair shading does not function like Phong shading in that it utilizes surface normals - diffuse shading of hair utilizes the hair tangents.
Hair Material • 103 Note: If you have simultaneously applied the “Transparency” channel, it may be necessary to increase the “Translucence” value in the Illumination channel, since hair with a higher level of transparency will itself allow more light to pass through it. The following two effects are chiefly responsible for giving hair a realistic look when rendered: 1. Translucence, which lets light pass through the hair. 2. Transparency (Transparency channel), which makes hair visible through other hair.
• Hair Material Self-Shadow Left: A lower “Self-Shadow” value. Right: A higher “Self-Shadow” value. Use this slider to adjust the strength of the shadow on the hair itself. Back Shadow This setting is primarily designed to adjust the light on the reverse side of the hair (as seen from the origin of the light source). This setting also has an effect on the Received Shadow and on the Self Shadow. “Back Shadow” is designed for fine-tuning all shadow effects on the reverse side of the hair.
Hair Material • 105 Screen This is the opposite of the Multiply blend mode. The background pixels and blend pixels are inverted, multiplied, and inverted again. This mode generally gives a result brighter than the background. Darken The background and blend pixel will be compared and the result will always be darker. Lighten This is the same as darken except the result will always be lighter. Difference The background and blend pixels will be subtracted from each other.
• Hair Material Glow The color of the background pixels and blend pixels will be swapped. The result will be similar to Hard Light mode. Freeze The background pixels and blend pixels will be inverted and the result inverted again. Heat Like Freeze mode but the background pixels and blend pixels will be swapped. Add One of the simplest blend modes: The background pixels and blend pixels are added.
Hair Material • 107 Polygon Hair Shader General If you want to render polygon hair, CINEMA 4D offers the Polygon Hair Shader, which can be found in the “Luminance” channel of any normal CINEMA 4D material. Polygon hair is rendered similar to the way in which normal hair is rendered. Nevertheless, the Polygon Hair Shader offers only a fraction of the properties normal Hair material has to offer.
• Hair Material Shader Properties The properties outlined in the image above should already be familiar to you, as they have all been previously described. The functionality is also the same as previously described. The following three properties / settings are new: “Alpha Depth”, “Shadow Transparency” and “From Hair materials”. The effect of “Alpha Depth” and “Shadow Transparency” will only be visible if the shader itself has been loaded into a CINEMA 4D alpha channel.
Hair Material • 109 Shadow Transparency Use this slider to define the shadow strength of the more-or-less transparent Polygon Hair. The greater the value, the more transparent the hair will be. From Hair materials If you should want to render Polygon Hair that should only be made polygonal during rendering (i.e. you don’t want to convert them with the “c”-key), you can apply the Hair shader to the Hair object. All relevant (real) Hair material properties will be assumed by the shader.
4 Hair Object
Hair Object• 111 Hair Object General Guides and Hair To begin with, something you should always keep in mind: Guides are not hair. Where guides are present hair must not necessarily grow. Nevertheless, hair can grow where no guides are present. In which areas hair roots can be placed is determined primarily by these three factors: An object, Selection Tag or vertex map, which can be placed in the “Link” field of the “Guides” tab. A texture placed in the “Density” field of the “Hairs” tab.
• Hair Object Unrooted Guides Guides will basically follow any movement the object makes, onto which they are rooted . Nevertheless, guides can still be unrooted (uprooted): By using the “Unroot Guides” tool. By over-manipulation of hair-covered polygon surfaces, on which guides had already been planted. Unrooted guides will be depicted with a green circle around the root.
Hair Object• 113 You should already be familiar with these settings from CINEMA 4D (see chapter 7 in your CINEMA 4D reference manual). What’s new and interesting in Hair, though, is the “Priority” setting. Use this setting to define the refresh rate of the Hair object (see also chapter 17 in your CINEMA 4D reference manual). The following will be refreshed: The guide roots.
• Hair Object Guides can grow on the following objects / elements: All objects made up of geometry, polygonal or parametric. Splines Other guides Guides will normally be generated if: You select “Add Hair” while an object is selected; after having added weighted points; while a point-, edge-, or polygon selection is active (see chapter 2).
Hair Object• 115 1. Geometry Polygon Left: Polygon mode. Right: Polygon Area mode. The guides will be distributed randomly across corresponding polygons. This bears the disadvantage that very small polygons will be assigned many more guides in relation to their size than large polygons. If you want the guides to be distributed evenly, independent of polygon size, select the next option, “Polygon Area”.
• Hair Object Custom Select this option if you want to, for example, add guides using the “Add Guides” tool. 2. Splines From left to right: Spline Vertex; Spline Segment; Spline Uniform; spline Tip (“Growth” set to “Random”); Spline 2D. Spline Vertex A maximum of one guide point will be added, base on the value entered for “Guide”. Spline Segment Guides (the amount will be defined by the “Count” setting) will be randomly distributed along the length of the spline.
Hair Object• 117 Custom This option does not work in conjunction with splines. 3. Guides Tip: If you arrange guides onto other guides, a second Hair object will be created. The sequence with which the Hair objects will be calculated is important! Make sure the initial Hair object (i.e. the object on which the hair grows) is arranged in front of the subsequently created Hair object in the Object Manager. Hair Vertex A new guide will be created at each guide point.
• Hair Object Unroot: Basically works like the “Old” option, except that newly created guides will be unrooted, preventing changes from being made to the hairstyle. Hence, deleting polygons on which hair grows will not delete the corresponding guides, as would be the case if you used either of the previous two options. So, use this option if you definitely want to avoid the hairstyle from being affected by changes to the underlying mesh. Nevertheless, unrooted guides do offer several disadvantages.
Hair Object• 119 Splines as guides. Left: Active Hair object. Right: Active Spline object. The guides will then be linked with the Spline object. If you switch to point mode and click on the Spline object, the guides will be treated as splines and can be edited accordingly. If you subsequently select the Hair object, you will see that the guides have conformed to the spline. You can also edit the guides using the Hair tools, which will, in turn, affect the spline.
• Hair Object Symmetry Left: Initial state. Center: “Show Guides” active. Right: The guides after “Make Editable” was pressed. “Symmetry” is designed for such instances when, for example, only half a head was modeled, and mirrored using the CINEMA 4D Symmetry Tool. You can then position guides on the half of the head that was modeled first, and mirror them onto the subsequently created half. To activate this function, simply activate the “Symmetry” setting.
Hair Object• 121 Hairs Tab The settings in this tab define the physical properties of the hair that will actually be rendered. These properties can, for example, also be made invisible by corresponding Hair material settings or by the settings in the “Culling” tab. These hairs, which far outnumber the guides, will be interpolated between the guides. Count This setting defines the actual number of hairs.
• Hair Object Segments From left to right: 3, 8, 48 segments, respectively. As you already know, there is also a “Segments” setting for guides. The “Segments” setting here performs the same function, only for the hair. Higher values cause the hair to be more flowing. Higher values also cause render times and processing requirements to increase accordingly.
Hair Object• 123 Root Use this setting to define where the hair should be positioned on the underlying object. The same applies here as was described for the “Root” setting in chapter 4, the only difference being that a disproportionately high number of hair roots to hair will be positioned.
• Hair Object Left: “As Normal” not active. Right: “As Normal” active. Both examples use the flat guide shown in the inset. Offset Top: Positive “Offset” value. Bottom: Negative “Offset” value. Use this setting to offset the hair in the direction of the surface normals. A value of “0” means the hair roots will lay directly on the hair-covered surface. “Offset” can be used for special effects, such as a cartoon figure’s eyelashes, or if certain Hair materials (e.g.
Hair Object• 125 Growth Remove Invalid If active, all hair that does not maintain the minimum distance from other hair, as defined in the “Restrict to Guides” or “Density” settings, will be removed (scaled to “0”, to be exact). Min. Spacing If hair is distributed randomly, as is the case with most root types, some hair may be positioned very close together. This can be avoided by defining a minimum spacing between hairs.
• Hair Object Restrict to Guides The guides on the left were used to create the clumps on the right with the “Restrict to Guides” setting. Activate the “Restrict to Guides” setting if you want the hair to be arranged only in a specific radius around the guides. The “Distance” setting defines the size of this radius. The “Guides” setting defines the number of guides that should positioned within the “Distance” setting, so the hair can be rendered.
Hair Object• 127 Root / Tip Use these settings to define the distance the root and tip (each separately) of the cloned hair may diverge from the original position of the hair on the X- and Z -axes. In the example above, the tips of the bristles were varied more than were the roots. This resulted in the final bristles spreading at the tip. Scale / Variation Use the “Scale” setting to define how much larger or smaller the cloned hair should be compared to the original hair.
• Hair Object From Guides Interpolated hair searches for the guides nearest to it and will conform accordingly. “From Guides” defines the degree to which individual hairs will be influenced by the guides (hair located closer to the guides will be influenced to a greater degree). The larger the value entered for “From Guides”, the more flowing and homogeneous the interpolation between guides will be.
Hair Object• 129 Various interpolation settings and their resulting effects. At the top left of the image below, the distribution of guides is shown, as used for each of the examples.
• Hair Object Fill Hairs Tab Fill hairs constitute an additional layer of hair: 1. First, you have guides, between which a large number of hairs will be interpolated. 2. Then there is the “normal” hair, between which the fill hair is interpolated. Simply said, fill hair is additional hair that is interpolated between existing hair when the scene is rendered. This lets you render objects with a lot of hair, even millions (e.g. fur), while keeping render times down and saving on memory.
Hair Object• 131 Only three “real” hairs, between which 1000 fill hairs have been interpolated. As you can see, fill hair is created exclusively by the interpolation between existing hair, and distributed evenly across the surface. Fill hair does not take into account the restrictive hair root distribution, which can be defined in the “Growth” menu in the “Hairs” tab. Other restrictions can be encountered as opposed to using “real” hair. For example, (hair) partings cannot be made (“Partings” tab).
• Hair Object Clump Activating this setting will cause the fill hair to form clumps by attracting it to the nearest “real” hair. This is basically the same function as the “Clump” setting in the “Interpolation” menu of the “Hairs” tab (only difference being the “Interpolation” setting). Attraction Use this curve to define the strength of clump creation along the length of each fill hair.
Hair Object• 133 Use the “Display” setting to define how guides should be displayed in the editor view: None: Guides will only be displayed when the corresponding object is active. Guide Lines: Guides will always be displayed (in blue) when the corresponding object is not active. Guide Polygons: Guides will be displayed as shaded polygon stripes. Hair Lines: Guides will be displayed as blue lines, in accordance with the “Detail” setting.
• Hair Object LOD Use this setting to define how the CINEMA 4D level of detail (e.g. editor view: Display / Level of Detail or in Project Settings) should affect how hair is displayed: None: Ignores all defined levels of detail. All: Level of detail will affect hair roots and hair segments. Count: Level of detail will only affect the number of hairs. Segments: Level of detail will only work on hair segments.
Hair Object• 135 Glass hair with an area shadow, as shown in the image below, can only be created using the CINEMA 4D renderer. If you want to create a similar effect, simply apply a normal CINEMA 4D material to the Hair object: Hair rendered using the CINEMA 4D renderer: Transparent, refracting hair, and area shadows on the floor. If you want to render polygonal hair with lighting properties similar to those of the Hair material, use the polygon hair shader (see chapter 3, “Polygon Hair Shader” ).
• Hair Object The following types of generation are available (each is affected by the hair and segment settings in the “Hairs” tab): None No polygons or splines will be generated. Spline A spline segment of a common spline object will be generated from each real hair (does not work with fill hair). Flat A flat polygon band will be generated from each real hair (does not work with fill hair).
Hair Object• 137 A cone that was replicated using “Instance” (define the thickness in the “Thickness” channel of the Hair material). Object Place the object, from the Object Manager, into this field that should be used in place of the hair. Make sure that the object is made up of as few polygons as possible, since memory requirements can increase dramatically once the object is instanced. Axis This setting defines along which axis the instanced object will run along the hair.
• Hair Object Hierarchy If more than one object is instanced, the sequence in which the objects are applied from the hair root can be defined using “Hierarchy”. The original objects must be child objects (in the Object Manager) of the object located in the “Object” field of the “Generate” tab. The hierarchical sequences listed below are available. The examples are based on the following scenario: 4 objects are used – A,B,C & D. Objects B,C and D are all child objects of object A.
Hair Object• 139 Examples: Various “Instance” options (all have “Scaling” set to “Fit). Clockwise from top left: Deform “None”; “Bend”; “Align” and “Hierarchy” set to “Forward” (using a cone object, with a capsule object and a platonic body object set as children). Frame Update If shaders are animated in the Hair material (e.g. in the “Displace” channel in order to simulate hair billowing in the wind), activating this option will refresh the generation type at each frame.
• Hair Object Local Use this setting to define which coordinate system should be used. Invert Rotates the elements to be aligned by 180°. They will show in the exact opposite direction of the “Alignment” setting. Single Object Use this setting to define if polygon hair or spline hair should be converted (“c”-key) to a single object or if each hair should be converted to a separate polygon object (setting not active) or spline object (setting active).
Hair Object• 141 Use the options in the “Axis” setting to define in which direction the polygons created using the previous “Slice” option should be arranged: Hair: The polygons will be perpendicular to the hair tangent. Camera: The polygons will point in the direction of the camera. Normal: The polygons will only point in the direction of the surface normals at the hair root.
• Hair Object From left to right: Rest state; frame 10; frame 40. You can also take a look at the spline dynamics system, located in the Spline Dynamics Tag (see chapter 5). How do dynamics affect hair? Let’s say you’ve already created guides, including hair: Click on “Play Forward” in the Time Manager tool palette. The guides will fall under the influence of the applied gravity. Simple! Note: Make sure no Hair tool is active! If so, dynamics will not be animated in the editor view.
Hair Object• 143 A simplified depiction of the arrangement of dynamics springs. Imagine this arrangement of springs attached to each guide (all springs simultaneously serve to push or pull), which ensures that the guides do not simply collapse when a force is applied. The guide pictured above consists of three segments. The arrangement of springs also functions the same with guides containing more segments.
• Hair Object Note: A perfect sphere (“Render Perfect” active) used as a collisions object will be calculated using a special accelerated mode. You can, for example, place an invisible “perfect” sphere at the head and shoulders of a character in order to prevent the hair from penetrating these areas. Initially, this may require a little more setup work than directly defining collision detection between guides / hair and head and shoulders, but the reduced render times will pay off in the end.
Hair Object• 145 Hold Roots Use this setting to adjust the stiffness of the anchored root segments. Higher values will result in more voluminous hair that will not lie directly on the scalp. Drag Use “Drag” to drain energy from the movement of the guides. The effect can be compared to hair moving in a liquid or substance with a higher viscosity. “Drag” can also be used to suppress unwanted twitching of hair, which can occasionally occur. Stiffness The effect of stiffness.
• Hair Object Hold Roots If you have unrooted hair (hair around whose base a green circle is visible), the roots of this hair can be affected by dynamics. To avoid this, activate the “Hold Roots” setting. Rest Mix Use this setting to mix the rest state with the current guide position. Internally, dynamics will not change: If you set “Rest Mix” back to 0%, you will notice that dynamics will proceed as before. So, what’s this good for? Well, let’s say you’ve applied dynamics to hair.
Hair Object• 147 Example: Below, the guides on the right half of the head were assigned a maximum strength (red). “Rigid” is active and “Stiffness” is set to 100%. The Hair Vertex Tag in the “Stiffness” field ensures that the hair with the least amount of stiffness (blue) will fall, while the hair with the maximum “Stiffness” value (red) remains completely straight. A Hair Vertex Tag is used to control the stiffness of hair at the vertex level. The other “Maps” fields work the same.
• Hair Object In the graph (inset), each guide has a maximum “Rest Hold” value over 2/3 of its length. Most of the remaining 1/3 of each guide has a “Rest Hold” value of “0”, and is therefore affected to the maximum degree possible by gravity. All other modifiers work the same. Advanced Dynamics The “Advanced” menu settings let you define if and how dynamics should affect only guides or each(!) hair. In most cases, the “Guides” option can be used.
Hair Object• 149 Iterations This setting can be used to further influence the tension of the springs. In general, the higher the value, the stiffer the guides will be. As a rule of thumb, a value equal to the number of segments should be used (very large values will at some point have no additional effect, and will only serve to further slow render times). The settings in the “Advanced” menu generally will not have to be changed.
• Hair Object Gravity This is basically the common force we’re all familiar with from our lives on planet earth. By default, this setting has a negative value (-Y in the world coordinate system) - after all, gravity doesn’t cause you to “fall up...” If desired, a positive value can be entered. Radius A force field around each guide. This radius represents an imaginary tube around each guide, containing a force effect with an adjustable falloff that affects other guides.
Hair Object• 151 Falloff / Curve Falloff types: Constant, Linear, Square, Cubic. Use this function graphs to define the falloff between the guide and the effect radius defined in the “Radius” setting. Use the “Custom” option to define a custom falloff. What can “Hair to Hair” be used for? If we take a look at the brush from earlier in this manual, you will see that the bristles all stand perpendicular to the surface, giving the brush an unrealistic look.
• Hair Object Cache Tab “Cache” lets you temporarily save dynamics calculations and play them back. This allows the scene to be played much more smoothly in the editor view. The calculated and cached dynamics simulation (hereafter referred to as “solution” ) is saved (cached), including the scene itself, and can be rendered using NET Render. You can also save and load solutions separately. Dynamics Cache If this setting is not active, dynamics will be calculated.
Hair Object• 153 Partings Tab So, what’s a parting? A parting is nothing more than a border at which hair lies in opposing directions. Ok, so all you first need to do is plant two guides that point in opposite directions, right? Well, yes, but...hair will also be interpolated between these two guides as well, and no clear line of separation will be visible. This is where “Partitions” comes in.
• Hair Object Angle This is the maximum difference in angle the guide root segments can have for hair to still be interpolated between them. If the actual difference in angle between these two guides is greater, no hair will be interpolated between them. If the “Distance” setting should not play a role, set its value very high. Groups Groups that have been assigned a Hair Selection Tag using “Set Selection” can be placed into this field.
Hair Object• 155 Near Clip / Near Fade From the angle of view of the camera, hair that lies closer than the defined “Near Clip” distance will be reduced to a thickness of “0” within the defined “Near Fade”. Far Clip / Far Fade From the angle of view of the camera, hair that lies beyond the defined “Far Clip” value will be reduced to a thickness of “0” within the defined “Far Fade”.
• Hair Object Redistribute Loops When new guides are grown (“Guides” tab), Hair checks (internally) if the conditions set in the “Growth” menu are met (e.g. minimum distance apart). By default, twenty passes are made in an effort to meet the conditions defined. If the conditions cannot be met within the defined number of passes, no more passes will be made. Use this setting to define the number of passes that should be made.
5 Objects and Tags
• Objects and Tags Objects and Tags The Feather Object General The Feather object is a special Hair object that is specially designed for creating bird feathers. Follow these steps to create your own bird feathers: 1. Create one or more splines that will define the rachis. 2. Select the Feather object and make a spline a child of the Feather object. 3. The width and shape of the feather is adjusted using “Barb Length” in the “Spacing” drop-down menu. 4. Apply a Hair material to the Feather object.
Objects and Tags • 159 Settings Object Tab Show in Editor This option must be activated if you want the feather hair to be displayed in blue in the editor view. Editor LOD Use this setting to define the Level Of Detail of the feather hair in the editor, i.e. how many of the hairs will actually be displayed in the editor view (this is dependent upon the “Spacing” menu settings). Generation Use this setting to define how the feather hair will be treated, as hair or as splines.
• Objects and Tags Spacing There are two methods with which the spacing of the feather hair, the so-called barbs, can be regulated: Fixed: Spacing will be regulated by the settings in the “Spacing” menu. Adaptive: The number of Barbs will indirectly regulate the spacing. If the spline length is animated and the amount of feather hair changes in order to maintain correct spacing between hairs (this will happen if the “Fixed” option was selected), flickering can occur.
Objects and Tags • 161 Barb Spacing / Variation If “Fixed” spacing has been selected, enter the distance between hairs here. Use “Variation” to randomly vary the spacing for a more realistic look. Barb Count If the “Adaptive” option is selected in the “Spacing” menu, enter the number of feather hairs in “Barb Count”. Barb Length Use this setting to define the maximum feather hair length, which is restricted by the Shape Tag’s “Shape” function graph.
• Objects and Tags Displace A view along the length of a feather: Left, a lower “Displace” value; right, a higher “Displace” value. The barbs can be curved along their profile by using the “Cross Section” graphs in the Form tab. The “Displace” setting simply defines the strength with which the barbs will be curved perpendicular to the spline tangent. Rotation Rotation Step / Variation From top to bottom: Lower, middle, high value.
Objects and Tags • 163 Enter lower values here as well, since higher values can lead to a feather duster effect. Rotation / Variation Use this setting to rotate the entire feather hair around the spline. This can be practical if the hairs happen to be pointing in the direction of the camera, and thus cannot be seen. The hairs can then be quickly rotated 90°.
• Objects and Tags Gaps Intermittent gaps make a feather look more realistic. Use this setting to define the size of the gaps between barbs. If several gaps are already present, and the number of gaps is again raised using the “Gap” setting, gaps lying in close proximity to one another will be closed. It is not recommended that the “Gap” settings be animated, since they can start jumping from one location to another. Variation Use this setting to randomly vary the size of the gaps.
Objects and Tags • 165 Shape Use the “Form” graphs to give the outer edge of your feather a unique shape. Each side can be adjusted separately. The maximum Ycoordinate length is defined by the “Barb Length”, which is used to define the length of the feather hair. Cross Section The “Cross Section” graphs let you adjust the height of each side of the feather separately. The maximum Y-coordinate length is defined in the “Displace” setting of the “Displacement” drop-down menu.
• Objects and Tags Curve Use the “Curve” graphs to reshape the individual feather hair points (number of points set in “Segments” in the “Object” tab). Each half of the feather can be adjusted separately. The graphs can have negative or positive values - a horizontal line in the center is a neutral position. The hair roots will be displaced as well, which means that the feather hair can be moved past the defined end of the feather.
Objects and Tags • 167 Hair Material Tag General The Hair Material Tag is automatically created when you add hair to an object or selection by selecting “Add Hair”, or if you apply hair to an object as a whole. This Tag’s primary function is to correctly mix materials for hair that has numerous materials applied to it. How can numerous Hair Material Tags be mixed? You can apply as many Hair materials as you want to a Hair object.
• Objects and Tags This setting is only of importance if an additional Hair Material Tag already lies to the left of the selected Hair Material Tag. If the first Material Tag is applied to the hair (“Remove Available” active in this Tag), the second Tag can only be applied to any hair that remains. If this setting has been deactivated, the selected Tag will (depending on its settings) more or less affect all hair with its Hair material.
Objects and Tags • 169 Clumps Circular clumps with “Clump” applied (red). If you want numerous Tags to be dispersed as clumps, this is the right option for you. This Tag creates only circular clumps of hair (the hair will not merge at the tip). “Amount” regulates the number of clumps that will be created in relation to the amount of hair to be rendered. If, for example, you have a total of 1,000 hairs, an “Amount” value of 1% will result in a maximum of 10 clumps being created. A value at or around 0.
• Objects and Tags Example: Left, a soft transition; right, a more abrupt transition. In the image above, two Hair materials (thick red and thin green hair) have been applied to the Hair object. If you want to use the texture shown in the insert at the top left of the image, the following prerequisites must be met: The left (red) Tag: “Remove Available” must be deactivated, and “Use” set to “All”.
Objects and Tags • 171 Mix In the background, each material is shown on a separate Hair object; in the foreground, both colors are shown on a single Hair object: Left, a “Mix” value of 30%; right a “Mix” value of 70%. This setting lets several Hair materials affect the same hair to varying degrees. Not only can hair color be mixed, the Hair material settings can be mixed as well! In order for this to take place, both “Use & Remove Available” options must be deactivated and “Use” set to “All”.
• Objects and Tags Note: If you want to texture hair using this method, the “Vertex Sampling” option in the “Render Presets / Effects / Hair Render” menu must be deactivated! Symmetrical This option will apply the texture to the hair in the following manner: The texture will be mirrored to the left (hence the name “Symmetric” ) and applied in the U-direction through to the tip of each hair, and in the V-direction from the center of each hair to its outer edge.
Objects and Tags • 173 Feather “Feather” mode with a spline shader. The text is deformed in accordance with the “Feather” settings (insert). This option was specially designed for use with the Feather object. Use this option to apply a texture to the entire feather. The texture can be place precisely, using the Level shader’s “Transform” effect. The applied texture will follow any distortions applied to the feather.
• Objects and Tags Draw This setting determines whether or not the constraints should be shown in the editor window. Set Clicking this button will connect the selected guide points or spline points with constraints, which in turn are connected to geometry points on the other side. Release Click this button to “free” the selected guide points or spline points from the constraints. Clear Click this button to delete all constraints. Object Drag a polygon object from the Object Manager into this field.
Objects and Tags • 175 Offset “Offset” lets you move the fixed points in the direction of the constraint lines. This offset will be displayed in the editor. An “Offset” value of “0” will fix the points directly on the object. Influence Map / Offset Map In the example above, a vertex map is used to define the influence: Left 100% (yellow) to right, 0% (red). Vertex Tags can be placed into each of these fields.
• Objects and Tags Hair Collider Tag If the dynamics or spline dynamics defined in the Hair object should affect other objects with regard to collision (or force fields), assign a Hair Collider to the corresponding Hair object. The following options are available: Collisions Use this setting to switch collision on or off for the corresponding object. Friction Imagine dynamically-controlled guides falling onto a sphere with a Hair Collider Tag assigned to it.
Objects and Tags • 177 Forces The cylinder in the center exerts a repelling force on the guides (in this case, “Falloff” is set to “Constant”, i.e. the radius remains constant). Activate this option if objects should exert forces on guides or splines. Make sure that the “Surface to Hair” option is activated in the Hair object’s “Forces” tab. Tip: In order to adjust the influence of the guides or splines, you can even drag the object with the Collider Tag assigned to it around the editor window.
• Objects and Tags Falloff / Custom Falloff from left to right: “Constant”, “Linear”, “Square”, “Cubic”. Use these graphs to define the falloff between the object surface and the radius defined in the “Radius” setting. Use “Manual” to create your very own falloff. Restrict If you want to restrict the collision to a selected area of the collision object, you can drag the corresponding polygon selection tag into this field. This can save a lot of time when working with very complex objects.
Objects and Tags • 179 Restore Selects the selections that were saved to the Tag and switches to the correct mode. You can also double-click on the Tag. The following keys can be pressed while making a selection: SHIFT: Converts the selection according to the currently selected mode. CTRL: Converts the selection according to the currently selected mode and selects the entire guide as well.
• Objects and Tags The settings framed in red can also be found in the Hair Render menu’s Shadow tab in the Render Settings. The Light Tag lets you change these settings at the (light) object level and apply different settings to each light. A light source must have its own type of shadow already defined. If the light source has its shadows deactivated, activating “Soft Shadows” in the Light Tag won’t do any good. Include This setting defines whether or not a light source should illuminate the hair.
Objects and Tags • 181 Properties Enable This setting lets you turn the Render Tag on or off. Auto Time See the “Trail” option below. Mode Point This mode is designed for use with polygon objects and lets an individual hair be grown on a geometry point. Surface This mode is designed for use with polygon objects and lets hair grow randomly on the object’s polygons. Line This mode is designed for use with splines and renders each spline or spline segment as a single hair.
• Objects and Tags Position This mode is designed for use with particles. It renders a very small “hair point” for each particle. The size of this “hair point” can be defined by applying a Hair material and assigning the Thickness channel’s “Root” and “Tip” settings equal values. Velocity This option will render a tangential velocity vector as a hair, at the position of each particle. The hair length can be varied using “Scale”.
Objects and Tags • 183 Auto Time By deactivating “Auto Time” the “Start” and “Stop” settings are made available, with which you can determine the exact time span within which a particle stream’s flight path should be analyzed and rendered as hair. If this option is active, the default settings will apply (see “Preferences” in your CINEMA 4D reference manual). Limit “Limit” active. If “Limit” is deactivated, the entire flight path of the particle stream will be rendered as hair.
• Objects and Tags As Fill Hairs If you drag a Hair material directly onto an object it will be completely covered more or less only with fill hair. Fill hair brings with it several disadvantages, such as not being visible behind transparent objects or not being able to be mirrored. With “Fill Hair” you can tell transparent objects or objects that reflect to render these hairs (expect increased memory demands and longer render times).
Objects and Tags • 185 Count Enter the amount of hair for polygon-based hair or hair interpolated between spline segments. Polygon objects will produce a homogenous distribution of hair only if all polygons are of the same size, since large polygons are given just as much hair as small polys. Segments Use this option to change the number of hair segments. By default, the hair generated is straight as an arrow, and the number of segments it has is basically irrelevant.
• Objects and Tags Tag Tab Collision Use this setting to determine if the splines should be checked for collision with other objects containing a Hair Collision Tag. Rigid Activate this setting to stiffen the springs connecting the mass points. The spline will try to maintain its shape without simply falling/ collapsing, as it would if this option were not active. The splines will sway at or near their initial state, depending on rigidity.
Objects and Tags • 187 Radius Use this setting to define the radius around the spline within which “Collisions” should have an effect. The higher the value, the further the spline will sway over the surface of a collision object. Stiffness Basically, “Stiffness” defines to what degree the springs will affect the splines. Low values will offer less resistance to gravitational and other forces, higher values will offer more resistance to these forces.
• Objects and Tags Mass / Set Use the “Mass” setting to assign mass to your spline points. A large spline point mass will place greater strain on the springs, which will, as a result, be stretched further. A “Mass” setting of “0” affixes the point (this point will not be moved by the spline dynamics). Fixed Select the spline points you would like to use as anchor points and click on “Set”. This will fix these spline points and they will not move.
Objects and Tags • 189 Dynamics Cache If this setting is not active, dynamics will be calculated. If this setting is active, the cached solution will be used. If no solution was cached, dynamics will be calculated. Calculate Clicking this button will calculate the dynamics, and a solution will be created and cached. “Dynamics Cache” will subsequently be activated automatically, and the cached solution can be viewed in the editor view.
• Objects and Tags Iterations This setting is an additional way in which spring stiffness can be influenced. Generally speaking, the higher the value, the more stiff the springs. As a rule of thumb, values equal to the number of hair segments should be used. Anything higher would simply increase render times without having any additional effect. Auto If this option is active, dynamics will be calculated over the entire length of the project (Edit / Project Settings).
6 Render Settings
• Render Settings Render Settings Settings for the Hair renderer are located in the “Effects” tab in the “Render Settings” menu. The Hair renderer will be activated automatically when Hair, a Hair material or a Hair Render Tag is created. The Hair renderer menu lets you define settings for transparency, shadow, lights and outputting Multi-Pass Hair.
Render Settings • 193 Vertex Sampling If this setting is active, light, shadow and color of the hair will only be calculated on those points defined by the segments and interpolated over the remaining part of the hair. Activating this setting will let you render faster and will, in most cases, produce good results. If more exact rendering is required, deactivate this setting and the calculations will be pixel-based. This will also increase render times.
• Render Settings Tracing Memory As soon as raytracing is applied (“Raytrace” mode or “Reflection / Refraction / Traced Shadows” active), various amounts of memory can be allotted. As usual, the more memory allotted, the faster the rendering will be (within limits: if memory must be allotted from the hard drive, rendering will slow accordingly). Shadows Tab First off: If you want hair to cast shadows, use “Soft Shadows”.
Render Settings • 195 Transparent Threshold / Depth Threshold A short description of how shadow maps function in Hair: Special “depth shadow maps” are used that calculate shadow maps for each individual light (from the point of view of each light), and save varying states of shadows (pixel by pixel) in the distance. This is necessary, for example, in order to effectively cast shadows in a room in which numerous partially transparent “objects” and hair are combined.
• Render Settings Shadow Map Increasingly large shadow maps from top to bottom. Notice also the slight change in the shadows cast within the hair itself. This is the most important setting, aside from the type of shadow itself. Use this setting to define the resolution of the shadow map. Larger maps will result in more precise shadows. This applies to shadows cast by hair onto other objects, as well as shadows cast within the hair itself.
Render Settings • 197 Lights Tab Use the “Mode” setting to define whether a light source should be included or excluded with regard to lighting and shadow casting. Simply drag the corresponding light source(s) into the “Lights” field from the Object Manager. Objects Tab Hair Use this setting to define if hair on Hair objects should be rendered. Polygon If you assigned a (Hair) Render Tag to a polygonal object without assigning it a Hair material, hair will be applied to the complete object.
• Render Settings Length / Count (Hair) “Length” and (Hair) “Count” apply to objects to which only a Hair material was applied, without using a Hair object. Use this setting to globally define length and count. Length and count can also be defined for each object individually in the (Hair) Render Tag. Mode Use this setting to define if the objects (if any) placed in the “Objects” field should be included in or excluded from rendering.
Render Settings • 199 Depth / Alpha Use this setting to define if and how depth and alpha passes will be output for the rendered hair. The following options are available: None: No hair depth or alpha passes will be output. Standard: Both passes will be integrated into the CINEMA 4D depth and alpha passes (“Alpha Channel” must be active in the “Save” menu of the CINEMA 4D “Render Settings” menu). Separate: Each pass will be output separately.
7 Preferences
Preferences • 201 Preferences A Hair menu has been added to your CINEMA 4D preferences menu (Main Menu / Preferences...). This menu contains preferences pertaining to Hair. Auto Add Post Effect If this option is activate the Hair renderer Post Effect, necessary for rendering hair, will automatically be activated when: The “Add Hair” command is executed, when a “Render” Hair Tag is applied, or whenever otherwise deemed necessary.
• Preferences Object Modify Undo If you edit an object containing guides, on which hair has grown (e.g. delete a polygon), guide roots can be rearranged, which will have an effect on the hairstyle. If you do an Undo, this step will be undone. If you also want the guide roots to return to their exact previous position with no change to the guides whatsoever, this option must be active. Activating this option will save relevant Hair object settings in the Undo memory, which also requires more memory.
8 Hair Nodes
• Hair Nodes Hair Nodes General Included in Hair are several special Hair Nodes, whose primary purpose is the detection of position and collision of hair or guides (or other elements located thereon) with other objects. You can select a Hair Node in the XPresso editor by right-clicking on the XGroup window and selecting one of the six available Hair Nodes in the “New Node / Hair / General or Iterator” menu.
Hair Nodes• 205 Mode Use this setting to define which guides or hairs will be used: Guides: The “normal” guides in their state of rest. Dynamic Guides: The guides affected by Hair dynamics. Hairs: The hairs themselves. Input Ports Point Enter the point data for the user-defined point in space to which the proximity of the nearest point on the hair or guide should be ascertained. Output Ports Guide The number of the guide nearest the user-defined point is located here.
• Hair Nodes Hair Collision Use this node to detect guide collisions (and the collision properties - position, speed, etc.) with any object containing a Collisions Tag. This is done for each frame of animation. This node contains the following input and output ports: Input Ports Object This is the object whose guides should be checked for collision. If this node is active, the corresponding Hair object can also be placed into the “Reference” field.
Hair Nodes• 207 Object Use this node if you want to output colliding points from polygonal objects. To do so, connect the “Object” and “Polygon Index” output ports to the input ports of the same name on a Polygon Node. Objects that actually collide with the guides are always beside the “Object” output port. Polygon Index This Node constantly outputs the polygon numbers (these numbers can also be found in the Structure Manager) of the colliding polygons.
• Hair Nodes Mode Use this setting to define which segment number and how many guides or hairs should be read out: Guides: The number of segments defined in the Hair object’s “Guides” tab. Dynamic Guides: The settings defined in the “Advanced” menu of the Hair object’s “Dynamics” tab (a separate number of segments can be defined for Hair dynamics). Hairs: The number of hairs and segments defined in the “Hairs” tab.
Hair Nodes• 209 Input Ports Additional input ports can be activated within the Node: On A Boolean value that will turn the Node on or off. Dynamics Position This setting lets you affect the dynamic guides directly. Each guide point can be set arbitrarily. Velocity Use this port to pass on velocity as a vector. Segments / Guides / Segment Delta Use these three input ports define exact positions on guides or hairs: Guides, segments, and each individual guide point are numbered.
• Hair Nodes Using a setup as shown above, objects or object points can be placed precisely on guide or hair positions. Index Internally each guide and hair point has a unique consecutive number, which can be addressed individually. The numbers can be used with the “Index” input port to, for example, to connect a Hair Selection Node that contains all points within a given selection. Add Force This setting will pass on forces as vectors, upon which dynamics will have an influence.
Hair Nodes• 211 Force Use this port to pass a force on to an input port. This force will be added internally to the dynamics forces, the sum of which will then be output. Mass Use this port to define the mass. The mass will generally be varied along the length of the entire guide (“1”). Mass can also be varied according to point, using the Hair object’s “Dynamics” tab.
• Hair Nodes Input Ports This Node contains the following input ports: On This is a Boolean value that will turn the Node on or off. Tag Connect a (Hair) Selection Tag’s “Object” output port to this port. Output Ports Count This Node outputs the number of elements selected. Iteration This output port can, for example, be connected with a Hair Point Node’s “Index” output port. Index numbers of guide points, hair points or of guides, will be output.
Hair Nodes• 213 Mode Use this setting to define which guides or hairs should be checked for intersection: Guides: The “normal” guides, not those controlled by dynamics in their rest state. Dynamic Guides: The guides controlled by dynamics (internally, these are seen as copies of the guides in their rest state, which are affected by dynamics). Hairs: Each individual hair can be checked. Velocity Mode Select between “Per Second” and “Per Frame”, depending on the velocity setting.
• Hair Nodes Segment Delta This port outputs the exact position at which a given segment was intersected. A value between “0” (segment start) to “1” (segment end) will result. Position This port outputs the point of intersection on the guide containing the velocity vector as vector.
Index• 215 Index Symbols 32-bit 192 8-bit 192 A AA quality 193 Additive 88 Add guides 44 Add Hair 11, 17 Align root 48 Alpha depth 108 Amount (bend channel) 90 Amount (clump channel) 85 Amount (curl channel) 93 Amount (displace channel) 87 Amount (frizz channel) 75 Amount (length channel) 72 Amount (scale channel) 73 Amount (straighten channel) 100 Amount (twist channel) 97 Amount (waves channel) 98 Angle (curls tool) 39 Angle (partings tab) 154 Animated shaders 58 Applying Hair material manually 56 Area
• Index Collision 186 Collisions 143, 176 Collisions (brush tool) 29 Colors 61 Color (color channel) 59, 62 Color (specular) 65 Comb 33 Converting Hair objects to polygons 107 Count/segments (editor tab) 134 Count (add guides tool) 45 Count (fill hairs tab) 131 Count (guides tab) 114 Count (hairs tab) 121 Cross section (feather object) 165 Curl 93 Curls 38 Curve (clump channel) 86 Curve (clump tool) 37 Curve (comb tool) 34 Curve (feather object) 161 Curve (frizz channel) 76 Curve (thickness channel) 70
Index• 217 GI 214 Grass 13 Gravity 150, 188 Growing hair 11 Growth 118 Grow selection 24 distance 24 neighbors 24 Guides 14, 117 custom 117 guide tip 117 hair guides 117 hair lines 117 hair vertex 117 Guides (mirror tool) 47 Guides (push tool) 43 Guides are not hair 111 Guide modes 18 guides 18 next vertex 18 points 18 previous vertex 18 root 18 tips 18 vertex 18 Guide root segment 28 H Hair 14 Hair channel sequence 56 Hair collision (XPresso) 206 Hair components 15 Hair guides 117 Hair IK 29 Hair intersec
• Index M R Make editable 120 Making hair polygonal during rendering 109 Mapping Hair materials 56 blend Hair materials 56 Hair channel sequence 56 projection 56 Mass 144 Material editor 55 hair 55 Hair materials and objects 55 quality 55 Min. spacing/distance (guides tab) 118 Min.
Index• 219 convert selected 23 deselect all 24 Grow selection 24 intersecting 23 Invert 24 select all 24 unrooted 23 zero 23 Select pushed 42 Self-shadow 104 Set as dynamics 12 Set roots 48, 126 Set selection 26 Shadows 62, 131, 194 Shadow map 196 Shadow transparency 109 Shape (feather object) 165 Shortening guides 11 Show all 25 Show guide 120 SKY 214 Soft shadows 194 Spacing (feather object) 160 Splines 116 custom 117 spline 2D 116 spline guides 116 spline segment 116 spline tip 116 spline uniform 116 s
• Index invert 68 texture 68 white 68 Transparent threshold 195 Tweak (soft selection function) 50 Twist/variation (clump channel) 82 Twist function graph (clump channel) 84, 85 Type (generate tab) 135 Type (hairs tab) 127 U Unlock all 25 Unlock selected 26 Unrooted guides 112 Unroot guides 112 Update frame 152 UV 115 UV grid 115 UV tag 156 V Variation 128 Variation (clump channel) 85 Variation (curl channel) 93, 94 Variation (feather object) 164 Variation (frizz channel) 75 Variation (kink channel) 7
