8

122 Chapter 4: Object Properties
Displacement group
These settings let you apply displacement
parameters on a per -object basis.
Use Globa l S ettings—When on, applies to all
objects the Displacement settings on the Render
Scene dialog > Renderer panel >
Shadows and
Displacement rollout (page 3–111)
.Turnoffto
make settings on a per-object basis. Default=on.
V i ew-Dependent—Defines the space for
displacement. When View-Dependent is on, the
Edge Length setting specifies the length in pixels.
When off, Edge Length is spec ified in world-sp ace
units. Default=on.
Smoothing—Tur n off to have th e ment al ray
renderer correctly render height maps. Height
maps can be generated by normal mapping; see
Creating and U sing Normal Bump Maps (page
3–146)
.
When on, mental r ay simply smoothes the
geometry using the interpolated normals, making
the geometry look better. This result, however,
cannot be used for height map displacement
because smoothing affects geometry in a way that
is incomp atible w ith height mapping.
Edge Length—Defines the smallest allowable
edge length. The mental r ay renderer will stop
subdividing an edge once it reaches this size.
Default=2.0 pixels.
Max. Displace—Controls the maximum offset, in
world units, that can be given to a vertex when
displacing it. This value can affect the bounding
box of an object. Default=20.0.
Tip: If displaced geometry appears to be “clipped,”
try increasing the va lue of Maximum Displace.
Note: When using placeholders (see the Translator
Options rollout (page 3–115)
), if this value is larger
than it needs to b e, it can reduce performance. If
youexperienceslowtimeswhiledisplacedobjects
when Use Placeholder Objects is on, try lowering
the Max. Displace value.
Max. Level—Controls how m any times a t riangle
can be subdivided. Default=6.
User De fi ned Pa nel ( Obj ect
Properties Dia log)
Edit menu > O bject Properties > Object Properties dialog
>UserDefinedpanel
Select object or objects. > Right-click. > Transform
(lower-right) quadrant of the quad menu > Properties >
Object Properties dialog > User Defined panel
Layer manager > Click the icon next to an o bject’s name.
> Objec t Properties dialog > User De fine d panel
This p anel of the Object Propert ies dialog lets
you enter propert ies or comments t hat you define
yourself.