In the 3D character production process, after the mapping is completed next is the game character skeleton building. The human body is muscle-driven bones, bones play a supporting role for the human body, and the movement of the game character is driven by the bones, facial expressions also need to be facially bound first. Build the skeleton to produce the subsequent animation.
After the skeleton is built, it is time for skinning. Since the character skeleton and character model are separated in the process of 3D character production, the process of binding the muscles and skin to the corresponding skeleton to ensure that the corresponding parts will follow the movement when the skeleton moves is called skinning.
Commonly used software for 3Dmax, Maya, MotionBuilder, 3Dmax character studio for retaining equipment and motion capture data. Maya commonly used a binding plug-in advanced skeleton rig, using humaIK to create bones.
About skeleton (Skeleton), binding (Rigging), skinning (Skinning), brush weights (Weight Painting)
3D animation models are composed of a large number of vertices (Vertex), and it is an impossible task to manually move such a large number of vertices to the specified position in every frame. So artists pay attention on the relationship between animal bones and skin and designed virtual bones for the model as well.
The Skeleton, called the Armature, is composed of a single bone, just like the human skeleton. We want to “combine” or “assemble” the bones and the model in some form, which is actually what we will call a skin later. In this way, each bone controls the vertices of the nearby area. When the bone moves, the skeletal joint will pull the bone it controls to move with it.
With the bones, it is much easier to control. But it is more convenient when posing for the role. So people borrowed the principles of mechanical design, designed several skeletal constraints, and by cleverly combining these constraints and adding some controllers, some complex may need to move many bones to achieve a pose, only move one or two controllers can be achieved. For example, the stomping heel pose is achieved with this binding structure.
Skinning is the process of combining bones and models. In Blender, it is a matter of a shortcut operation (Ctrl + P) and even assigning weights at the same time. Blender’s accompanying automatic weighting is so convenient and accurate that many times there is no need to manually brush the weights when using Blender for simple character skinning.
A single bone can control many vertices, and at the same time, a single vertex can be controlled by multiple bones. It is where we need to assign these bones to control over that vertex, and the control is called a weight. In 3D software, the most common tool to configure weights is similar to brush-like tools, so this process is also called brush weights. The same skeleton and the same model, the configuration of the weights are different, and the final generated animation effect will be very different.