9

1186 Chapter 9: Surface Modeling
surface as the original edge, or on a different
surface.
Offset Sur face
SelectNURBSobject. >Modifypanel>CreateSurfaces
rollout > Dependent Surfaces group box > Offset
Select NURBS object. > Modify panel > NURBS toolbox >
Create Offset Surface button
An Offset surface is offset a specified distance from
the original along the parent surface’s normals.
Surface created as an offset
Procedure
To create a n off set s ur f a ce:
1.
In a NURBS object that contains at least
one surface, turn on Offset.
2. Click the surface yo u want to offset, and drag to
set the initial distance of the offset surface.
The offset sur face is c reated.
3. Adjust the Offset par ameter.
Inter face
While an offset surface sub-object is selected,
a rollout with the offset Distance parameter is
displayed at the bottom of the Modify p anel.
Offset Surface rollout (creation time)
Offset—Thedistancebetweentheparentsurface
and the offset surface, in 3ds Max units.
If the p arent surface is planar, the appearance of
theoffsetsurfacedoesn’tchangewithdistance.If
the parent surface is curved, increasing the offset
value increasingly exaggerates the curvature of the
offset surface.
Flip Normals—Lets you flip the surface normals
at creation time. (After creation, you can flip
normals using controls on the Surface Common
rollout.)
Cap—When on, eight boundary curves are
generated (four at the four edges of each surface),
and then generates four ruled surfaces to connect
the two original surfaces. While they are present,
cap surfaces are maintained so they match the
dimensions of the offset and its parent.
The Cap check box appears only on the creation
rollout. If you want to remove the caps later,
simply selec t them as surface sub-objects and
delete them. Think of offset capping as a workflow
shortcut rather than a property (or parameter) of
offset surfaces.
To flip the norma l of an offset cap, select it as a
surface sub-object and use the Flip Normals toggle
on the Surface Common rollout.
Note: If you tr im the original sur face, or ma ke the
offset surface independent and then trim it, the
capping surfaces will look str ange.