A few questions about scene->mRootNode.

[Lucipetus]

Is it always an extra node that ASSIMP adds while importing? It appears to be so when I'm importing exports from blender (I'm not familiar with how blender exports its scene, but at least blender's hierarchy doesn't show a root node).

It looks from the source mRootNode->mTransformation isn't necessarily identity, if not what kind of transformations may be stored there? What are the sources of the transformation? Can there be translation, that is, not at the origin?

This bothers me because I don't know if I should including mRootNode->mTransformation when importing models and animations. It looks like it's identity most of the time.

[kimkulling]

The root node of the scene is used to define the transformation in the world-space. When its located at (0|0|0) the transformation of the root-node will be an Identity-Matrix.
So for your import code when you want to use the model as an instance you can ignore this transformation and place the model stored in the scene by yourself.

Hope that helps!

[emeiri]

Does this mean that the reason why we multiply by the global inverse transform (tools/assimp_view/SceneAnimator.cpp:159) is to bring back the model into local space so that the application can set it in world space on its own?

Thanks,

Etay