Have you thought about more complicated things, like
some flesh bulging out when a join moves? Simply because
of conservation of volume. Are there restrictions on the
angle of the joints? Both things are not so well done
in Poser IMHO, there it is too easy to overstrecht and
even do 360 turns on any joint, which horribly deforms
the mesh. There is also the issue of the muscle contracting
giving mesh deformations at the position of the muscle
and not close to the joint.

Rune wrote:

> Rune wrote:
> 
>>Yes. Your format and the game-related formats I was looking at seem
>>to have in common that each vertex is attached to one bone only, not
>>multiple bones, each with a weight of influence.
> 
> 
> Actually the Unreal skeletal model format does have multiple-bone influence
> on vertices, as it can be seen in this document:
> http://udn.epicgames.com/Two/SkeletalSetup
> 
> My guess is that any serious skeletal mesh format that is under active
> development will end up supporting this. Having each vertex attached to one
> bone only simply is too restrictive.
> 
I think that the one vertex one bone and even the Unreal model are set up
to fascilitate fast computation. In the context of ray tracing this is
not so much an issue (unless we do real time ray tracing). If I had
to do it I probably start with something of the Unreal model as a first
approximation and then for a number of angles of the joint compute
the position of the vertices. Then do a sort of relaxation step to get
the mesh a bit nicer, and perhaps account for compression effects.
Finally fit a curve through the positions as a function of the joint
angle. That is a lot of computation, but it has to be performed
only once for the model.
I did something like that in my butterfly model
http://news.povray.org/povray.binaries.scene-files/thread/%3C402136A0.7020206%40hotmail.com%3E
(yes I know I had only one 'joint' and a combination of joints makes
it more difficult)

	Andrel

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