9

148 Chapter 17: Rendering
Shadows Map
A shadows map saves only the shadows cast onto
the object.
Component Options (Selected Eleme nts Unique
Settings)
There are no unique settings for a shadows map.
Lighting M ap
A lig hting m ap saves only the lighting cast onto
the object.
Component Options (Selected Eleme nts Unique
Settings)
For a lighting map, you can choose not to render
shadows, direct light, or indirect light.
Nor mals Map
A normals map saves a color gradient that indicates
the direction of normals on the surface of the
object. With a normals map, Direct3D rendering
canmakesimplegeometryappearmorecomplex.
With DirectX 8, you can view a normals map
in shaded viewports by using the Metal Bump
Direct3D viewport shader (page 2–1614).
With DirectX 9, you can view a normals map in
any shaded viewport.
Component Options (Selected Eleme nts Unique
Settings)
Therearetwouniquesettingsforanormalsmap:
Output into Nor mal B ump—When on, assigns a
Normal Bump map to the Target Map Slot, and
places the rendered Normal Bump map in the
No rmal component of the Normal Bump map
(page 2–1731).Default=off.
Render Height Ma p i nto Al pha Channel—When on,
renders a grayscale height map and assigns it to
the alpha channel of the Normal map. If you are
rendering to a file type that doesn’t have an alpha
channel, this setting has no effect. Default=off.
Height M ap
A height map is a g rayscale map that stores the
relative height of the source object when you
render with normal projection. (See Creating and
Using Normal Bump Maps (page 3–150).) You can
use the height map as a displacement map on the
target object. This is a way to add detail to the
edges of the low-resolution object, because edges
are not affected by the normal bump map itself.
Note: When using a heig ht map as a displacement
map with the mental ray renderer , be sure to
use the Height Map Displacement shader (page
2–1722).Also,turnoffSmoothing,either
globally or for the individual object on the Object
Properties dialog > mental ray panel (page 1–126).
In addition, when rendering with mental ray,
if you’re applying the height map to a standard
material, apply the m ap as a Displacement map on
the mental ray Connection rollout (page 2–1461)
(unlock the map first), not on the Maps rollout.
Tip: Using a paint program such as Adobe
Photoshop on a height map is possible, but prone
to error. The values in the height map depend
on the shapes of both the low-resolution and
high-resolution models, and it’s easy to damage
the mathematical accuracy. If you p aint any
changes onto the map, be careful to preserve the
facetedlook,andavoidthetemptationtoblur
away the facets. You might try painting in Additive
or Subtractive mode, to add to or subtract from
the displacement, because Normal mode will set a
fixed displacement, making it difficult for an artist
to control the result.
Component Options (Selected Elements Unique
Settings)
There are no unique settings for a heig ht map.