Skinning Method 2: Post Weights & Interactive Bind

In total, there are two methods of weighting; interactive and post (interactive weights are covered in another blog post). Both are equally effective, but both have characteristics that could benefit certain modelling situations. Post weights are more mathematical, whereas interactive weighting is more artistic. Choosing a method is mostly down to personal preference.

Post Weights

Once the joints and outer shapes have been bound, the weights need to be distributed in order to prevent distortion when joints are moved.

Unlike ‘interactive weighting’, ‘post weighting’ doesn’t delete existing weights once a joint has been ‘flooded’. The object in the image below shows how the pelvis has been flooded and the component editor will reveal that the total weight of the object now has a value of 2 rather than 1. The other joints can have weight subtracted, which wasn’t optional with ‘interactive flooding’.

Once the weights have been subtracted (only the pelvis remains with a value of 1), the process is similar to ‘interactive weighting’; vertexes are selected around specific joints and the area can be re-flooded. However, this won’t change weight on the pelvis joint, so we need to add weight to the selection, and subtract the exact same from the pelvis joint.  This process is completed for each joint up the leg in order to complete the grouping process.

Similarly to ‘interactive weights’, ‘Post Weights’ need to be painted in order to remove any breaks in the geometry during movement. Painting creates softer weight placement.

The component editor can be used to adjust distorting edges by selecting all its vertexes and shuffling weight about. Subtraction can be used because a value of 1 has already been established.

Interactive Binding

Interactive binding is a way of initially weighting a model. Moving the capsules will change how much influence they have in different areas. Red represents high influence (value of 1) and this gradients down to the lowest influence signified by blue. The anchors around the capsule can be manipulated to move and rotate the bind. Using interactive binding helps to speed up the ‘post weighting’ normalisation process.

Deformities indicate that the area doesn’t have enough influence, and we are therefore starting to loose the model.