"Baking" animations down to the mesh bones

Forgive me if this post shows a certain naiveté about how animations work internally, but…

I want to use Blender to create characters with animations that will be used in Unity.

Now, most of the Blender rigs I’ve encountered have two categories of bones - those to which the mesh is skinned, and bones whose sole purpose is to make producing animations easier. An example of the latter are the IK bones. They don’t have the mesh skinned to them - they just indirectly affect the bones that do.

What I’m wondering is whether it is possible to create an animation in Blender using the full power of a rig, and then somehow “bake” the animation down onto the just bones to which the mesh is skinned so that the “extra” bones can then be deleted from the character.

Basic idea:

  • Create the character and animation in Blender file A
  • Save file A
  • Copy file A to file B
  • Inside file B, “bake” the animation down and then delete anything in the rig that doesn’t actually affect the mesh
  • Import file B in to Unity

The intent is to import into Unity the character mesh and only the bones that will affect the mesh, rather than having all those “extra” bones in the rig that Unity doesn’t understand and (if the baking can be done) won’t need.

Thanks in advance!

No, you can’t delete bones in a rig and expect it to still work the same way. Each bone affects other bones and are relied on for transform information, so if you deleted an IK bone that moves a leg or arm, those movements will be changed completely because that bone’s transforms are removed from the calculations that result in what you wanted.

This should happen by default, just export using Only Deform ticked. (and make sure only the bones you want are indeed deforming)

Yes, of course, if all you do is delete the bone without doing anything else. That was why I was asking about some kind of procedure to transfer the animation information to the deform bones. That was what I was referring to when is used the term “bake.”

Bake Action is a command used to bake animation data to either an armature or an object.
If you check Visual keying and Clear Constrants, it will bake all the visual information to the rig.

I’m not going to tell you some sort of perfect way to do it, rather I’ll give you a tip for something that you “can” do:

create deformation rig, them apply a copy transforms (or child of) constraint on all the bones, to the control rig.
While you “can” export the deformation rig as FBX, you’re free to bake the rig first (fbx performs a bake before export).

Excluding the setup and bake times, this would be the perfect method to have however a complex rig as you want and then export it as simple as possible. Though for using an over-complex rig like Blenrig, this would practically be your only option since it’s rig doesn’t export (trust me, I tried).