The motion capture software and the Motion Builder Program have an assumption built into their methodology that you will model the character in a tee pose. This is from a legacy of engineers designing the software to integrate Motion Capture. The Tee pose is considered to reduce the error in posture between models. The problem with this is that it introduces error into the musculature when you model it. In real life the Tee pose is quite extreme and the musculature of the shoulders is hugely strained. When the Tee pose is relaxed to a normal pose with a simple rig, the tension remains in the muscles so these local details have to be corrected later on with extra rigging and corrective blend shapes. A better system would be to have the reference pose as an A pose with is closer to natural and relaxed, this would produce more natural movement from simpler animation rig.
Using Motion Capture was one of the initial objectives of the project. The principle of the system is fairly simple, but the actual use is quite involved. We had a great deal of fun working together on the ‘shoots’.
I think my colleagues started the process believing that it would provide all the animation for the characters. This was never going to be the case. What the MoCap data provides is a base reference of natural movement, which acts as a good starting point for the animation.