8

500 Chapter 8: Modifiers
you can delete the or iginal object, or you can
keep it in your scene to use for other purposes.
Tip: UseDispApproxtodisplaceeditable
meshes. Use Displace Mesh for previewing,
as in the first item, but avoid using Snapshot.
The mesh created by using Displace Mesh and
Snapshot can have a hig h polygon count. This
makes it slow to use interactively, and c an cause
smoothing problems, w here the underlying
mesh edges are visible.
Inter face
TherolloutforDisplaceMeshletsyouchoose
which surface approximation settings are used to
produce the mesh.
Update M esh—Updates the mesh if you have
changed the displacement mapping and want
to see the results of the change. The mesh isn’t
updated automatically because that can become
extremely time consuming.
Custom S ettings—When tur ned off, Displace Mesh
uses default settings to subdivide the mesh for the
purposes of displacement m apping. When turned
on, the subdivision controls in this rollout are
enabled. Default=off.
Subdivision Displacement—Subdivides mesh faces
to accurately displace the map, using the method
and settings you specify in the Subdivision Presets
and Subdivision Method group boxes. When
turned off, the modifier applies the map by moving
vertices in the mesh, the way the
Displace modifier
(page 1–608)
does. Default=on.
Split M esh—Affects the seams of displaced mesh
objects; also affects texture mapping. When on,
the software splits the mesh into individual faces
before displacing them; this helps preserve texture
mapping. When off, t he software uses an internal
method to assign texture mapping. Default=on.
Tip: This parameter is require d because of an
architectural limitation in the way displacement
mapping works. Turning Split Mesh on is usually
the better technique, but it can cause problems for
objects with clearly distinct faces, such as boxes,
or even spheres. A box’s sides might 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 v iew) un less
you turn off Split Mesh. However, texture mapping
works unpredictably when Split Mesh is off, so
you might need to add a Displace Mesh mo difier
and make a
snapshot (page 1–438) of the mesh.
Yo u w o u l d t h e n a p p l y a
UVW Map modifier (page
1–905)
and t hen reassign mapping coordinates to
the displaced snapshot mesh.
Subdivision Presets group a nd Subdivision
Method group
The controls in these two group boxes specif y how
the modifier applies the displacem ent map when