Ragdoll Physics

출처 : http://en.wikipedia.org/wiki/Ragdoll_physics

해당 출처에서 Approaches만 보기 좋게 옮겨둔다.

=========================================================================================

Ragdolls have been implemented using Featherstone's algorithm and spring-damper contacts.^[1] An alternative approach uses constraint solvers and idealized contacts.^[2] While the constrained-rigid-body approach to ragdolls is the most common, other "pseudo-ragdoll" techniques have been used:

• Verlet integration: used by Hitman: Codename 47 and popularized by Thomas Jakobsen [1], this technique models each character bone as a point connected to an arbitrary number of other points via simple constraints. Verlet constraints are much simpler and faster to solve than most of those in a fully modelled rigid body system, resulting in much less CPU consumption for characters.

• Inverse kinematics post-processing: used in Halo: Combat Evolved, this technique relies on playing a pre-set death animation and then using inverse kinematics to force the character into a possible position after the animation has completed. This means that, during an animation, a character could wind up clipping through world geometry, but after he has come to rest, all of his bones will be in valid space.

• Blended ragdoll: this technique (used in Halo 2) works by playing a pre-made animation, but constraining the output of that animation to what a physical system would allow. This helps alleviate the ragdoll feeling of characters suddenly going limp, offering correct environmental interaction as well. This requires both animation processing and physics processing, thus making it even slower than traditional ragdoll alone, though the benefits of the extra realism seem to overshadow the reduction in processing speed.

=========================================================================================

 

보통 캐릭터의 사망 애니메이션을 연출할 때 자주 이용되는데, 요즘 FPS게임에서 주로 쓰여지고 있다.

이번 GDC2008에서 Nintendo DS에 사용된 향상된 Ragdoll Physics에 대한 session이 있던데,

들을만한 가치가 있을지는 글쎄..

 

실제로 우리게임에 적용되기도 거시기 하다.

어느 정도 Death Animation에 대한 Preset이 있어야 하는데, Animation을 제작하는 Cost가 너무 쎄서..

이거 할 바에는 아직 미구현인 Animation을 제작하는 게 훨씬 Cost대비 효율이 좋지 ㅋㅋ