Researching and creating the biped rig - Part 3

Continuing down Jason Wiser's rigging tutorial, I applied a Skin modifier to my mesh and added all of the correct bones to it. After that, I modified each envelope to give a rough idea of how each bone should influence the points on my mesh.

Looking at the image below, you can see that the red areas have a high influence over the bone whilst the blue areas have a low influence.

The main issue with using purely envelopes is that there are always areas where the vertices get squashed into strange formations. To fix these, you have to manually adjust the weights of vertices, deciding how much influence the surrounding bones should have on them. I learnt how the Weight Table worked in 3DS Max by reading through the official documents for them on the Autodesk website. Looking at the weight table below, you can see that the vertex selected has 40% influence from the forearm and 60% influence from the upper arm.

The first area I fixed was the elbow joints, where the arm gets squashed when bent. I previously wrote about how to build the joints so that they clip through each other when bent, and this was done here by making sure the vertices along the joint have at least 90% influence from their respective arms.

The same thing was done with the shoulder, making sure that there is a clean seam along the clipped joint.

The knees were badly deformed from the envelopes, with most of the vertices influenced too greatly from the upper leg. Doing the same as the elbows, the two loops that run across the knee were given 50% influence from each leg, creating a perfect bend.

To test the torso I added an extra section to my animation which rotates the three spine joints to one side, twisting the mesh. I found that the weights weren't perfect and smoothed them out accordingly.

I then fixed all of the other parts of the body, such as the feet and neck, making sure everything deforms correctly.