[Bf-committers] Collada importer/exporter kickout

[Juha Mäki-Kanto]

 My basic point is that to me it seems like going to collada means you
either haven't done object/armature animation yet or you're done with it
and happy to have it "baked" as per frame rot/loc/scale or matrices. I'm
not sure about most other programs so I'll just ask: what would be the
correct way in collada to handle a parent inverse- matrix in child-objects
(possibly has skew in it) and the "default" rest-pose attributed
translation+rotation between parent-child bones?

2012/1/15 Juan Linietsky <reduzio at gmail.com>

> The problem with importing/exporting of Collada and skeletons is not really
> that it doesn't match the internal representation.
> Animating 3D objects in a 3D Animation package is always done through euler
> angles, local or global, and that is easy to export
> seamlessly in Collada.
> But skeleton based models like characters almost always use IK or other
> sort of constraints which are impossible to convert back to euler due to
> gimbal lock issues, so the only way to reliably export skeletal animation
> is to export a full rotation snapshot either via a quaternion (which
> Collada does not support) or 4x3 matrix., and later optimize redundant
> keyframes to save storage space.
> So I think in short, it's the lack of support for constraints what makes
> Collada not very useful as an exchange format between DCCs, but yet it's
> still very useful for exporting to game engines.
>
> Juan
>
>
>
>
> On Sat, Jan 14, 2012 at 5:28 PM, Juha Mäki-Kanto <kiskosika at gmail.com
> >wrote:
>
> >
> >
> > The gist to me is that collada's transformations may not match a
> program's
> > internal representation and reinterpreting usually goes via collada data
> to
> > full matrix, possibly fix the matrix and then decomposite to curves.
> It's a
> > lossy conversion, key's should match but interpolation won't -> you need
> to
> > bake/key every frame when importing the curves.
> >
> >
> >
> >
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