9

1002 Chapter 9: Surface Modeling
Sur face Proper tie s rollout
Specifies surface approximation settings for
subdividing the editable mesh. These controls
work lik e the surface approximation settings for
NURBS surfaces (page 1–1078).Theyareused
when you apply a displacement map (page 2–1511)
totheeditablemesh.
Note: The Surface Prop erties rollout is available
only for editable mesh objects; it does not appear
in the Modify panel for an object to which
the Edit Mesh modifier is applied. With Edit
Mesh-modified objects , you can use the Disp
Approx modifier (page 1–628) tothesameeffect.
Subdivision Displacement—When on, faces are
subdivided to accurately displace the mesh,
usingthemethodandsettingsyouspecifyinthe
Subdivision Presets and Subdivision Method
group boxes. When off, the m esh is displaced by
moving existing vertices, the way the Displace
modifier (page 1–629) does. D efault=off.
Split Mesh—Affects the seams of displaced mesh
objects; also affects texture mapping. When on,
the mesh is split into individual faces before it is
displaced; this helps preserve texture mapping.
When off, the m esh is not split and an internal
method is used to assign texture mapping.
Default=on.
Tip: This p arameter is required because of an
architectural limitation in the way displacement
mapping works. Turning Split Mesh on is usually
the b etter technique, but it can cause problems for
objects with clearly distinct faces, such as boxes,
or even spheres. A box’s sides m ight separate as
they displace outward, leaving gaps. And a sphere
might split along its longitudinal edge (found in
the rear for spheres created in the Top view) unless
you turn off Split Mesh. However, texture mapping
works unpredictably when Split Mesh is off, so
you m i ght need to add a Displace Mesh modifier
(page 1–514) and make a snapshot (page 1–453)
of the mesh. You would then apply a UVW Map
modifier (page 1–922) andthenreassignmapping
coordinates to the displaced snapshot mesh.
Subdivision Presets group & Subdivision
Method group
The controls in these two g roup boxes specify how
the displacement map is applied when Subdivision
Displacement is on. They are identical to the
Surface Approximation controls (page 1–1239) used
for NURBS surfaces.