8

Creating Materials for Lightscape 579
•Avoidoverlappingsurfaces,anddonotuse
double-sided materials.
• Assign mapping coordinates to geometry that
will use a textured material.
• Try to keep polygon count to a minimum. Use
the Optimi ze modifier and use smoothing
groups to reduce the number of faces needed
for smooth surfaces.
• L ightscape calculates radiosity only for the
front side of a face. Check face normals of the
geometry. Lightscape ’s Orientation option
offers convenient methods for changing a
surface’s orientation.
• Ifyouplantousedaylightinaninteriorscene,
create surfaces for areas that wi ll be windows or
openings in Lightscape. In order to allow light
to flow through them they must be placed in an
opening in the geometry, not on a continuous
surface. These surfaces should fill the opening
in the geometry. Since the exporter uses
material assignments to mark windows and
openings, these surfaces can be faces within
more complex geometry.
• You should model transparent objects that have
a refractive index greater t han 1 so that they
are physically valid. For example, you should
model a pane of glass as two surfaces separated
by the correct distance.
• Before exporting, make sure your units are
properly set. If your scene uses photometric
lights, this is pro bably the case. If your scene
uses standard lights, realistic units mig ht
differ from your viewport settings. You can
choose Customize > Units Setup to find what
units your model has. Make this correspond
to the units in which you will export your
model. BecauseLightscapeisaphysically
based lighting renderer, it is essential that you
export a scene with physically accurate units to
obtain accurate lighting results. See
Exporting
Standard Lig hts (page 3–580)
.
Creating M aterials for Lightscape
These are guidelines for creating materials to
export to Lightscape. In general, Lightscape
materials are less complex than materials in
3ds Max.
• Only the diffuse texture gets imported into
Lightscape, so there is no need to set up other
texture maps. Other mapping types can be
applied after the solution file is imported back
into 3ds Max.
• The diffuse color corresponds to the reflective
color in Lightscape.
• Glossiness corresponds to the shininess of the
material in Lightscape.
• Opacity corresponds to the transparency of the
material in Lightscape.
• Tiling information is exported, but mirrored
and clipped textures are not supported by
OpenGL display in Lightscape. They can be
seen only by using the ray tracer.
• The index of refraction is im ported into
Lightscape.
• For accurate radiosity processing, it is
important to set the correct HSV Value of the
material. The Value controls the maximum
reflectance of the surface. If it is set too high, the
solution looks washed out and processing time
increases sig nificantly. Refer to the
Lightscape
User’s Guide
for more information on how to
set material properties.
• Ifyouarecreatingsurfacesforopenings(See
Creating Geometry for Lig htscape (page
3–578)
), then create a transparent material for
these surfaces. This material should not be used
foranyothersurfacesinthescene.
• In Lightscape, windows allow daylight to pass
through. If your scene has windows, ma ke sure
that the materials you use on the windows in
your scene are not used for other surfaces.