Re: [Opensg-users] Binding matrix

[Carsten N. <car...@gm...>]

	Hello,

On 09/26/2013 03:48 AM, cristupidmail wrote:
> I'm a really newbie to OpenSG!
> Could someone explain to me what the binding matrix does in the
> testSkinnedGeometry example?
> I've read that it's used to bind a joint and a vertex or something, but
> I need to understand it as well as possibile and this is not enough!

the binding matrix for each bone is the inverse of the bone's 
transformation when it was attached (or bound) to the mesh. This is 
needed because when the bone has the exact same transformation as at 
binding time you don't want vertex positions to be affected, i.e. the 
transformation matrix applied to a vertex should be the identity. When 
the bone is moved away from the binding transformation you want the 
vertices affected by the difference between the bone's current 
transformation and its transformation at binding time, which you get by 
multiplying with the binding matrix (= inverse of transformation at 
binding time).

	Cheers,
		Carsten