8

980 Chapter 9: Surface Modeling
B evel S moothing—
These sett ings let you set
the shape of the intersection between the
surface created by a beveling operation and the
neighboring patches. The shapes are determined
by the handle configurations of vertices at the
intersections. Start refers to the in tersection
between the sides and the patches surrounding
the beveled patch. Finish refers to the intersection
between the sides and the beveled patch or patches.
The following settings are available for each:
•
Smooth—Ver tex handles are set s o the angles
between the new patches and their neighbors
are relatively small.
•
Linear—Vertex handles are set to create linear
transitions.
•
None—Vertex handles are not modified.
Note: Set B evel Smoothing before the bevel is
performed; changing the sett ing has no effect on
existing beveled patches.
Sur face group
View Steps—Controls the grid resolution of the
patch model surface as depicted in the viewports.
Render Steps—Controls the gr id resolution of the
patch model surface when rendered.
Show Interior Edges— E nables the display of the
patch object’s interior edges in wireframe views.
When off, only the object’s outline is visible. Turn
on to simplify the display for faster feedback.
Use True Patch Normals—De termines how the
software smoothes the edges between patches.
Default=off.
When the check box is off, the software computes
the surface normals from the smoothing groups
of the mesh object to w hich the patch object is
converted before rendering. These normals are not
accurate, especially with a low View/Render Steps
setting. When the check box is on, the software
computes true patch normals directly from the
patchsurfaces,whichcangeneratemoreaccurate
shading.
In the illustration below, a sphere was converted
to Editable Patch format, and then a vertex was
moved toward the center and rotated. The sphere
onthelefthasUseTruePatchNormalsturnedoff,
and the one on the right has it turn ed on. In both
cases, View Steps was set to 8.
A p atch sphere with Use True Patch Normals off (left) and
on (right)
Miscellaneous group
Patch S mooth—Adjusts the tangent handles of
vertices belonging to selected elements to smooth
the surface of the patch object.
PatchSmoothsetsthehandlestoabsolute
positions based on the patch object geometry;
repeated applications have no effect.
Pa tch G rid s
Create panel > Geometr y > Patch Grids
Create menu > Patch Grids
You can create two kinds of patch surfaces in grid
form: Quad Patch and Tri Patch. Patch grids begin
as flat plane objects but can be modified into
arbitrary 3D surfaces by either using an Edit Patch
modifier or collapsing the grid’s modifier stack
down to an Editable Patch in the Modify panel.