I’ve had this one itching for a long time, so maybe a real pro can enlighten me.
I’m just a newbie tinkering with Blender & Unity3D. After a year or so of on-and-off I’ve gotten a pretty strong handle on how the Armature, bones, vertex groups, and weight painting interact; and I can even handle the action editor and NLA strips.
Something you can do in Blender is, you can make a modifier with a target object, and when you move the target object you can make pretty cool “animations” - you could even (I think) keyframe and animate the target object, animating the modifier in Blender.
The thing is, the modifier only exists in Blender- and it is not a part of an actual animation “action.” Use the Cast modifier as a hypothetical example: I cannot imagine a way to replicate, visually, moving a cast modifier target through an object in bone-based, keyframed animation.
I could probably fake it with a lot of bones, but that’s wrong and will not produce consistent results.
One approach I could use would be to make a series of static meshes moving the control object, then parse them into an array, and play that animation by switching out the mesh. This is undesirable for lots of reasons but totally possible, it’s just how “traditional” animation would work without bones at all.
The other approach is that you would write a vertex shader, which is beyond my understanding of Cg / HLSL / shaderlab, but I know it would involve some kind of transform matrix that would iterate and take action on each vertex in a mesh.
Using a vertex shader would be cool, but they’ve difficult to write and the computer would be busy calculating that deformation all the time. If you don’t need the source point or control object of your “animation” to by dynamic, it’s overkill.