Game Development Reference
effects in this chapter, such as the Depth
Matte and Depth of Field effects.
All the work we've done so far with this
effect has been to create a great map of the
Z-depth in this image. But this is only one
of the many channels that we can extract
with this effect. In the 3D Channel drop
down, change the value to Object ID. Now,
when you click on one of the 3D objects in
this scene (such as the car or the table), the
Info panel will display the object ID of that
object (Fig. 2.7).
Object IDs are identifying numbers
assigned to objects in a 3D program. If
you did not assign object IDs in your 3D
Figure 2.5 The Info panel displays the distance from the
camera to the background.
Figure 2.6 The corrected
program, if you did not export your fi le with those object IDs, or if
your fi le format does not support them, this feature will not work.
Later on in this chapter, when we cover the ID Matte effect, we'll
use these object ID numbers to quickly isolate different objects in
our 3D scene.
Now change the 3D Channel drop down to Surface Normals.
Surface Normals display a color value for the direction that each
polygon is facing. This may seem like a bunch of random colors
at fi rst glance. But when we cover the Shift Channels effect in
Chapter 5, we'll use this data to add a new light in this scene as if
we had added it in the original 3D scene.
There are several other settings besides the ones that we've
covered. But the above listed options in the 3D Channel effect