The extension of these ideas to 3D and to multiple segments is conceptually straightforward, although there may be many pitfalls. For example, in the two segment case, it is not necessary to use the absolute orientation as part of the training parameters for the forearm shape. However, the texture values don't match between the two segments if different training parameters are used (one parameter instead of two). The challenge will be to maintain the continuity of appearance over the body even when different sets of training angles are used for different segments.
The example shown in this paper is equivalent to warping both example images to the target orientation and then linearly interpolating shape and texture. However, the RBFs provide a convenient formalism for warping many example images together.