The RealiTools OrthoVU plug-in is a Shader plug-in, and can be activated from the Surfaces panel. Its operation is relatively simple, so it has no interface. Essentially, what it does is let you render without perspective distortion. To use it, you apply it to a surface (usually a single polygon) that is visible to the camera. When that surface gets rendered, at each point, a ray will be traced out into the scene from that surface in the opposite direction of the surface normal. This means that, in actuality, you could use any shape you want. If you wanted a fish-eye effect, you could use half of a sphere. When using it, you'll want to put an object past the surface with OrthoVU applied, if you want to see the effect on that object.
Tutorial
Since it isn't always immediately obvious how to
use OrthoVU, let's go through a quick tutorial.
1. Open Layout and load building.lwo.
2. Rotate its heading 45 degrees.
3. Move it on the Y axis so it's about in the center of the camera
view.
4. Test-render a frame (F9). See how the sides of the building
angle off into the distance?
5. Load OVplane.lwo
and position it so it completely covers the camera's field of view.
Render.
Now see how the perspective that was on the building before is gone? That's what OrthoVU does. This kind of effect can be useful when you're doing technical-type illustrations, logos, shooting textures for real-time 3D models, or even rendering backgrounds for side-scrolling games! Here's what my finished scene looked like.