9

970 Glossary
have default smoothing groups. The default
material ID assignment depends on the type of
geometry. Most curved objects such as spheres
have a single material ID. Boxes have six IDs, one
for each side. Cylinders have three: ID number 1
and2forthetwocaps,andIDnumber3forthe
sides. Hedra have three: one for each of their P,
Q, and R axes.
When you apply a Multi/Sub-Object material,
the materials will match the Multi/Sub-Object
mater ial ID numbers to the material ID numbers
on the faces of the object. Fa ces keep a record of
the ID number, and not of the material name. If
the material is anything but Mu lti/Sub-Object, the
material is assigned to the object’s entire surface.
Assigning some defining material ID number to
each object before they become compound object
operandscanbeausefultechniqueforbeingable
toselecttheseparatepiecesafterthey’recombined.
You can use material IDs for continuous surfaces
that require separate paints or finishes. For
example, a car constructed from different types of
materials, such as a colored metal body, chrome
parts, glass windows, and so on.
Yo u c a n u s e t h e Material modifier (page 1–714) to
assign material ID numbers. Also you can reassign
materialIDsusingtheEditableMesh>Surface
Properties rollout, or Edit Mesh modifier > Edit
Surface rollout.
Material/Map Hierarchy
Material/map hierarchy shown in the Material/Map Navigator
TheMaterialEditorcouldbecalledtheMaterial
and Map Editor, because you can use it to design
both materials and maps, and any combination of
the two . In addition, you can create ma terial or
map hierarchies.
A material hierarchy is a material that consists
of other m aterials (or m aps). Similarly, a map
hierarchy is a map consisting of other maps.
Materials that consist of other materials are
called compound materials ( page 3–922).Maps
consisting of maps ar e compound maps.