[Bf-committers] Collada importer/exporter kickout

[Juan Linietsky]

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.
>
>
>
>