骨骼动画

顶点动画：帧动画

骨骼动画：模型里面有一根根骨头，通过控制骨骼（bone），骨骼带动皮肤（skin）来移动（实时计算皮肤顶点的坐标，耗CPU），带骨骼的模型叫做mesh。

物理引擎可以控制骨骼移动，如布娃娃系统，把刚体绑定在骨骼上，从而控制骨骼移动。

Early video games used manually created animations for characters' death sequences. This had the advantage of low CPU utilization, as the data needed to animate a "dying" character was chosen from a set number of pre-drawn frames. As computers increased in power, it became possible to do limited real-time physical simulations. A ragdoll is, therefore, a collection of multiple rigid bodies (each of which is ordinarily tied to a bone in the graphics engine's skeletal animation system) tied together by a system of constraints that restrict how the bones may move relative to each other. When the character dies, their body begins to collapse to the ground, honouring these restrictions on each of the joints' motion, which often looks more realistic.

The term ragdoll comes from the problem that the articulated systems, due to the limits of the solvers used, tend to have little or zero joint/skeletal muscle stiffness, leading to a character collapsing much like a toy rag doll, often into comically improbable or compromising positions.