Friday Workshop Week 2: Skin Weights

In this week’s workshop, we started expanding on the rigging from last week and began to skin weight joints to the mesh.

Skin Weighting in Blocks

The first step was to block the skin weighting to key sections of the mesh and use a flooding technique to feather out the weight at the edges in a way that is controlled, particularly by the vertices you select.

The fingers were the most tricky area to flood, because of the sheer amount of vertices and the distance between each other. The important aspect of this selecting the influence of the correct joint and then using this flooding technique (ensuring that the influence is low) to create a somewhat seamless crease between the different parts of the finger.

Skin Weighting in Blocks

One of the issues I encountered with this process early on was during the skin bind, I selected the hierarchy of the mesh in the incorrect order, which led to the following issues. In order to fix this, I deleted the skin binding history and started again selecting everything correctly.

Issues with Hierarchy selected in Skin Bind

Starting again, I decided to tackle the skin weighting within the fingers, as this proved to be the most ‘fiddly’ and vertex dense area to consider. The main thing that helped during this process was flooding the weighting 100% to their respective joint, and then selecting the vertices in the mesh that were added with the design of deformation. This is highlighted in our own hands in the areas where lines appear between the skeletal joints of our hands and fingers. By adding a slight percentage of flooding, the two areas blend into one another, creating less mesh collision. However it its a careful process as too little weight consideration can lead to volume inconsistencies upon rotation.

Initial Skin Influence Issues
Vertex Flooding
Weight Adjustment with Vertex Flooding
Weight Adjusting Finger
Weight Adjusted Finger
Fully Influence Elbow Joint
Influence Adjusted Elbow
Fully Influenced Shoulder Joint
Skin Weigh Shoulder Joint
Skin Weighing Armpit Influence

One of the trickier areas of skin weighting was the centre of the body, as the if the skin weigh is not somewhat evenly distributed between the different spinal joints, the deformation would appear blocky and entirely inaccurate to human anatomy.

Blocked Skin Weights

As seen below, I was initially having a few issues getting the chest/ armpit and stomach areas to rotate side to side without mesh collisions, and using the same technique as the fingers I was eventually able to create an even spread between the different joints, getting a more accurate skin weight than by painting it unevenly myself.

Mesh Obstruction

Adjusted Weight Influence

Incorrect Mesh Weighting
Correct Mesh Weighting

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