No deformation on Blender animated mesh?

I’m having a hard time getting my animations from Blender into Unity.
The armature bones all seem to be there, but they don’t deform the mesh.

Here’s what a test animation I have looks like in Blender vs Unity:

Blender animation

Unity animation

Seems to me like only the root bone is being rotated/moved in any way, but I don’t really know much about animations yet…

What can I do to investigate what the problem might be?

My procedure goes like this:

  • Create mesh, armature in Blender
  • Adjust envelopes, add Armature modifier to mesh
  • Create an action in the Action Editor, animate a bit
  • Export (I’ve tried both FBX and blend formats)

I’ve also tried different types of animation (legacy, generic).
I’m using Blender 2.68 and Unity 4.3.1f.

I figured out my problem: simply adjusting the envelopes works in Blender, but won’t affect the mesh in Unity. I had to paint weights onto the mesh for each bone before the deformation would show up.