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358 Chapter 5: Creating Geometry
•IfyoualterthePathStepsspinnerwhileinPath
Steps mode, the locat ion of your shapes might
change. An alert message warns you of this.
• If you animate the topology of the path while
in Path Steps mode (such as animating the
number of sides of an NGon), your shapes
might jump around trying to find a legitimate
position, and you could end up with more than
oneshapeonthesamepathlevel.
Pick Shape—Sets the cur rent level at any shape
onthepath.Whenyoupickashapeonthepath,
Snap is turned off and Pa th is set to the level of
the picked shape, where a yellow X appears. Pick
Shape is available only from the Modify panel.
Prev ious Sha pe—Jumps the path level from its
current location to the previous shape along the
path. A yellow X appears at the current level.
Clicking this button turns Snap off.
Next Sha pe—Jumps the path level from its current
location to the next shape along the path. A yellow
X appears at the current level. Clicking this button
turns Snap off.
Sk in Parameters Rollout
Select a path or shape. > Create panel > Geometry >
Compound Objects > Object Type rollout > Loft > Sk in
Parameters rollout
Select a path or shape. > Create menu > Compounds >
Loft > Skin Parameters rollout
On the Skin Parameters rollout, you adjust the
complexity of the mesh of the loft object. You can
also optimize the mesh by controlling the face
count.
Procedure
Ex ample: To use a constant cross-section:
1.
Enlarge the Front viewport to full screen, and
then draw a Rectangle object (page 1–272) with
Ctrl held down to create a square about 20
x20units.
2. Create another rectangle beside it about 200 x
100 units.
3. Apply a Skew modifier to the large rectangle,
but don’t alter the Skew parameters.
4. Create a loft object in which the larger rectangle
isthepathandthesquareistheshape.
5. On the Modify pa nel, open the Skin Parameters
rollout,andturnonSkinintheDisplaygroup.
Youcannowseethewireframestructureof
the lofted rectangle, with cross-sectional sides
parallel to its corners.
Make sure the color assigned the loft object is
easily visible. Change it if necessary.
6. Tu rn off Constant Cross-Section, and observe
the corners.
When Constant Cross-Section is off, the
corners become pinched.
7. Turn on Constant Cross-Sect ion to restore the
corners.
Acuteanglescancauseproblemswhenthecross
sections formed by the path steps intersect at
the corners. You can mitigate this by avoiding
acute angles or by reducing the path steps.
8. Press H on the keyboard to display the
Select Ob jects dialog (page 1–78),andchoose
Rectangle02 (the second larger rectangle).
9. On the Skew panel, change the Skew Ax is to Y,
and then set the Amount spinner to 95.
10. Use Zoom Region to zoom in on the upper-left
corner of the rectangle so you can see the mesh
in detail.
At a skew of less than 100, the acute angle still
works because the path cross-sections haven’t
intersected.
11. Set the Skew Amount to 300,andexaminethe
same corner.