Using a .c3d file

I imported a .c3d file from CMU motion capture database at a 120 frame rate. It doesn't give you the option to import as armature or empties, but instead comes straight in to blender with both. The file itself came with constraints, so all I needed to do was replace the same constraints to my own armature.

My armature had 5 spine bones but the imported only had two, so I had to put the constraints on the middle and bottom spine part. Another difference between the two armatures was the master bone, which was much smaller and pointing in another direction, so I changed mine to meet this. I had to change the parents of the legs when I removed my previous knee and leg constraints, and also reparent and connect the hips to the master. The constraints for the master bone were different to how I had seen before, it had a copy location but for the two hip bones, not the spine.

When I had constrained the entire upper body with IK, track to, and limit rotation, I looked at the sequence. Because of the way the head follows the empties the face is pointing down and goes into the mesh. I played around with the IK settings, removing use tail and using a chain length 2. This put the head up straight and 'corrected' the movement.


Problems with the hands were that they pointed backwards when relaxed, they looked fine when doing a straight punch. I edited the proportions of bones in the arm and improved it, but in the end I decided it would look better if I took out the constraints so it followed along with lower and upper arm parents.

The sequence worked very well and there was some really nice subtle movement being demonstrated in the video. One thing I thought
would make the animation really sharp was to get the eyes to move together with the animation, as they were focused on the eye constraint the whole time. So using keyframes I moved the eye constraint to where the hand was when it 'punched'. I adjusted the camera to keep everything in view, and ended up with this final result:



There is a part in the sequence towards the end where the character violently nods his head down, this is a fault in the mocap file and could have been due to magnetic interference, but other than that I'm really pleased with how it looks. If I can find more karate examples I can piece together my final animation. I will also base my previous mocap attempts on the constraints used here.