Rigid Animation
Rigid animation is used to move pieces of a 3D model. For example, you would use rigid animation to move the wheels of a car model. In this tutorial, we animate Microsoft's tank model using rigid animation.
Rigid animation is surprisingly simple once you start kind of grasping some of the matrix ideas that we've covered in previous tutorials.
Basically, how it works is that the model is created with what is called "Linked Objects" in 3D Studio Max. Every modeling program may have a different name for it, but basically it's just separate models that are linked together in a parent child relationship. Whenever you move the parent, all of it's children and there children's children and so on move together. If you move a child though, its parent (or parent's parent's parent) does not move. In this case, the tank body is the parent.
Files
Complete Project for Visual C# 2010 Express edition as a Compressed Zip file
Summary...
This is basically just my own rendition of Microsoft's tutorial on rigid animation. I thought I could do it better, so here's to giving it a shot.
Basically, this is just "How to animate the sub-meshes in a model". 3D Studio Max calls them "Linked Objects". For example, we learn how to rotate the axels, wheels, and turret of this tank model.