Editing Ragdoll physics (section)

{{short description|Type of procedural animation used by physics engines}}
{{Use mdy dates|date=April 2025}}
{{More citations needed|date=July 2011}}
[[Image:Animatsragdollphysics.jpg|220x220px|thumb|Still from an early 1997 animation using ragdoll physics]]

'''Ragdoll physics''' is a type of [[procedural animation]] used by [[physics engine]]s, which is often used as a replacement for traditional static death animations in [[video game]]s and [[Animation|animated films]]. As computers increased in power, it became possible to do limited real-time [[physical simulation]]s, which made death animations more realistic.

Early [[video game]]s used manually created animations for a character’s death sequences. This had the advantage of low [[Central processing unit|CPU]] utilization, as the data needed to animate a "dying" character was chosen from a set number of pre-drawn frames. In contrast, a ragdoll is a collection of multiple [[rigid body|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 [[Articulation (anatomy)|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. Modern use of ragdoll physics goes beyond death sequences.