Adding custom bone shapes

Armature bones are effective deformers, but we have experienced a major drawback for ourselves in the Using armature deformers section: bones tend to be hidden by the deformed geometry.

There are a few workarounds, such as activating the In Front attribute in the Armature properties and using X-Ray or Wireframe views.

Another gimmick consists in displaying special widgets by assigning mesh objects to the bone’s Custom Shape attribute.

Creating mesh objects in Python

First, we must create a new mesh. A mesh consists of vertex coordinates, plus edges or faces that connect vertices.

Figure 11.15: Vertex coordinates of a 2D square

In this example, we create a wireframe square and use it as a bone widget. Blender bones expand upon their Y axis, so the horizontal coordinates of our bones that are placed vertically are X and Z.

We build our list of vertices. We aim for a side length of 1.0, a measure easy to scale...