Interactive skeleton-driven simulation: Difference between revisions

Revision as of 13:05, 10 August 2006

Revision as of 10:24, 12 August 2006

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'''Interactive skeleton-driven simulation''' (or '''Interactive skeleton-driven dynamic deformations''') is a scientific [[computer simulation]] technique used to approximate realistic physical [[deformation]]s of dynamic bodies in [[real-time computing|real-time]]. It involves using [[elasticity_elasticity (physics)|elastic]] [[dynamics_dynamics (mechanics)|dynamics]] and [[optimization_optimization (mathematics)|mathematical optimization]]s to decide the body-shapes during motion and interaction with [[force]]s. It has various applications within realistic simulations for [[medicine]], 3D [[computer animation]] and [[virtual reality]].

==Background==

Methods for simulating deformation, such as changes of shapes, of dynamic bodies involve intensive calculations, and several models have been developed. Some of these are known as ''free-form deformation'', ''skeleton-driven deformation'', ''dynamic deformation'' and ''anatomical modelling''. [[Skeletal animation]] is well known in [[computer animation]] and 3D character simulation. Because of the calculation intensitivity of the simulation, few interactive systems are available which realistically can simulate dynamic bodies in [[real-time computing|real-time]]. Being able to ''interact'' with such a [[realistic]] 3D model would mean that calculations would have to be performed within the constraints of a [[frame rate]] which would be acceptable via a [[user interface]].

Recent research has been able to build on previously developed models and methods to provide sufficentlysufficiently efficient and realistic simulations. The promise for this technique can be as widespread as [[mimic]]ing human [[facial expression]]s for [[face perception|perception]] of simulating a human actor in real-time or other [[cell (biology)|cell]] [[organism]]s. Using skeletal [[constraint]]s and parameterized force to calculate deformations also has the benefit of matching how a single [[cell]] has a shaping [[skeleton]], as well as how a larger living organism might have an internal bone skeleton - such as the [[vertebrae]]s. The generalized external body force simulations makes [[elasticity]] calculations more efficient, and means real-time [[interaction]]s are possible.

==Basic theory==

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*a hierarchical basis containing functions which will provide values for deformation of each lattice [[___domain]] with calculations of these hierarchical functions similar to that of [[lazy evaluation|lazy]] [[wavelet]]s

Rather than fitting the object to the skeleton, as is common, the skeleton is used to set constraints for deformation. Also the hierarchical basis means that detail levels can be introduced or removed when needed - e.gfor example, observing from a distance or hidden surfaces.

Pre-calculated [[pose]]s are used to be able to interpolate between shapes and achieve realistic deformations throughout motions. This means traditional [[keyframe]]s are avoided.

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==Algorithmic considerations==

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To achieve interactivity there are several optimizations neccessarynecessary which are implementation specific.

==Projects==

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*''[http://grail.cs.washington.edu/projects/deformation/ Deformable Objects and Characters project]'', University of Washington, USA. Has example videos of the techniques.

*''[http://grail.cs.washington.edu/projects/charanim/ Motion Libraries for Character Animation project]'', University of Washington, USA. Has example videos of the techniques.

[[Category:Animation]]