8

1194 Chapter 9: Sur face Modeling
Adding a cap to a par tial lathe
Lathe Surface rollout (modification time)
Degrees —Sets the angle of rotation. At 360 degrees
(the default), the surface completely surrounds
the a xis. At lower values, t he surface is a partial
rotation.
Direction group
XYandZ—Choose the axis of rotation. Default=Y.
Align group
These buttons position the axis of rotat ion relative
to the curve.
Min—(The default.) Locates the lathe axis at the
cur ve’s negative local X-axis boundary.
Center—Locatesthelatheaxisatthecurve’scenter.
Max—Locates the lathe axis at the curve’s positive
local X-axis boundary.
Start Point—Adjusts the position of the curve’s
start point. This can help eliminate unwanted
tw ists or "buckles" in the surface.
This control is disabled if the curve is not a closed
curve.
Thestartpointisdisplayedasabluecircle.
Replace Base Curve—Lets you replace the parent
curve. Click the button, then click the new surface
on which to base the lathed surface.
Ruled Surface
Select NURBS object. > Modify panel > Create Surfaces
rollout>DependentSurfacesgroupbox>Ruled
Select N URBS obj ect. > Modify pane l > NURBS toolbox >
Create Ruled Surface button
A ruled surface is generated from two curve
sub-objects. It lets you use curves to design the
two opposite borders of a surface.
Using two curves to create a ruled surface
You can animate the parent curves or their CVs to
change the ruled surface.