9

HSDS Modifier 703
A control grid on a sphere at level 2. Sub divisions at lower
levels are visible as gold lines.
In wireframe views, you can still see polygons
at lower levels of detail, but you c an select only
sub-objects resulting from the subdivision, as
indicated by the control grid. You can subdivide
sub-objects further, transform them, hide and
delete them, and change material IDs.
Note: When you transform an HSDS sub-object,
the control grid tends to expand by adding
segments at its edges, in order to maintain
surface smoothness.
6. To subdivide a different part of the object,
choose a lower level in the Subdivision Stack,
and then repeat steps 2–4.
Each time you subdivide a sub-object that
has been subdiv ided, a higher level in the
Subdivision Stack is hightlighted, indicating a
finer mesh resolution. You can then work at that
level, or any lower level by selecting the level.
Note: Ifyoutransformasub-objectatalevel
lower than the highest level in which the subject
exists, the mesh uses the resolution imparted by
the detail in the higher levels.
Interfa ce
HSDS Parameters rollout
The sub-objects available in the HSDS modifier
belong to the control g r id rather than the mesh
object itself. Transforming the grid sub-objects
also transforms the underlying mesh, but the mesh
doesn’t always move to the full extent of the control
grid. Thisisparticularlytrueincaseswhereyou
transfo rm a sub-object at a level lower than the
highest level in which the sub-object resides.
For example, if you subdivide a vertex at the Base
Level, it then resides in the Base Level and Level 1.
Ifyouthenmovethevertexinthebaselevel,the
mesh doesn’t, by default, move as far as the vertex.
This is roughly analogous to the way free-form
deformation works, but with HSDS, the control
grid conforms much more closely to the shape of
the mesh object.
W ith vertices, you can control the degree to which
the mesh follows the control-grid vertex with the
settings on the Vertex Interpolation group.