                       Reflection Maps
                       ---------- ----

Handling reflections can be challenging. If you look around 
yourself, you will find that most artificial surfaces and
many natural surfaces are at least slightly reflective. Many
objects simply don't look right if they don't relect something.

One approach to reflectivity for which computers are
inherently suited is automatic, accurate calculation of
reflections through raytracing or automatic environment
maps. From an animation perspective, however, automatic
reflection generation is costly, due to the added rendering
requirements, and often wasteful, since comparatively few
real-world materials provide clear, discernable reflections.
We added this subdirectory of reflection maps to illustrate
how you can develop efficient, predictable reflection maps
when automatic generation is undesireable. In addition to
using these maps in your scenes, you can examine and customize 
them in 3D Studio (use the View Image command) or paint
software.

BURST.TGA      This abstract picture works well as a
               standard spherical reflection map, especially
               for beveled text.

CHRMWRK.TGA    This picture file is a work file for
               illustration purposes only; it shows how we
               manually created a cubic reflection map,
               CHROME.CUB. The image was airbrushed in Adobe
               Photoshop using a mask which defined the six
               200x200 pixel sides of the cube.

CHROME.CUB     An abstract cubic reflection map created in
               paint software. (See CHRMWRK.TGA and
               associated TGA files.)

CHROMEBK.TGA   Six views of CHROME cubic reflection map.
CHROMEDN.TGA
CHROMEFT.TGA
CHROMELT.TGA
CHROMERT.TGA
CHROMEUP.TGA

PATCHWRK.TGA   Wide aspect ratio mural used by overhead
               reflection assembly in STAGE.3DS (SCENES
               directory).

PURPLE.TGA     Abstract spherical reflection map.


Tips
----

An integral part of using reflection maps in 3D Studio is
the REFLECTION BLUR parameter in the Materials Editor. While
there are many reflective surfaces, few are truly mirror-
like. Most importantly, without blur, artifacts can appear
on flat and near-flat surfaces because they are reflecting
too small an area of the reflection map. Reflection mapping
results are generally best with REFLECTION BLUR set to 5 
or higher.

Many practical broadcast applications, such as flying logos,
rely heavily on reflection mapping for a glossy look. Seldom
do these logos actually reflect anything in the scene--they 
just shimmer. The challenge is to choreograph this shimmering. 
Because reflection maps have consistent orientation in the 
3D Studio universe, it is possible, with practice, to predict 
the reflections, and therefore control them. 

Reflections are dependent on the relationship of the
objects' surfaces to the camera, so the first step is to
finalize the keyframing of your scene. Reflection maps
correspond to the top, bottom, front, back, left, and right
sides of the 3D Studio universe (with spherical maps, the
"front" is the middle of the map, and the left and right
sides of the map meet at the "back"). Note that, by default,
3D Studio renders spherical reflection maps backwards; you
may want to set "REFLECT-FLIP = YES" in your 3DS.SET file
before continuing. The next step is to plan where in the
animation reflected highlights and colors should occur.
Then, considering the general area of the reflection map
that will be reflected by the geometry at a given point in
time, you can paint your reflection maps accordingly. While
experimentation is often necessary, neither precision nor detail
are. PURPLE.TGA is a good example of a map that might emerge 
from this technique.



