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FBX importing problems

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Hello. I'm trying to convert binary FBX files to my own format, which means extracting joints, vertices and bone bindings/weights from them, but I can't seem to get it right.

 

1. There are lots of transformation data in there. PreRotation, Lcl Translation/Rotation/Scaling, GeometricTranslation/Rotation/Scaling, PostRotation... I have no idea which transforms apply to what.

 

2. Due to the above problems, I'm having huge problems with importing joints/bones. The objects have a number of the above transforms, but in addition each deformer has both a "Transform" and a "TransformLink". None of these match each other. What am I supposed to base my joint transforms (bind pose) on?

 

3. My vertex positions and normal seem to match what I expect to get without any transformation applied to them, but I've found sources saying that they should be affected by Lcl and Geometric transforms. The model is rotated in ways I'm not expecting it to be with those applied though.

 

4. My model seems to only have bone bindings for a small subset of the model. Only 176 out of 750 vertices have any bone bindings at all. This may of course be a problem with the model, but it is being animated correctly in Maya, which confuses me even more.

 

I would really appreciate any help I could get. Thanks!

Edited by theagentd

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1. There are lots of transformation data in there. PreRotation, Lcl Translation/Rotation/Scaling, GeometricTranslation/Rotation/Scaling, PostRotation... I have no idea which transforms apply to what.

Try to focus on "Lcl Translation/Rotation/Scaling" (Lcl=local) first.

 


3. My vertex positions and normal seem to match what I expect to get without any transformation applied to them, but I've found sources saying that they should be affected by Lcl and Geometric transforms. The model is rotated in ways I'm not expecting it to be with those applied though.

Vertices and normals should be in object space, therefor unaffected by any transformation most of the time.

 

More advanced:

You should be more careful if you construct your mesh from multiple sub-meshes which are in relation to each other. In this case you should apply the transformation relative to the root object to position and normals.

 


4. My model seems to only have bone bindings for a small subset of the model. Only 176 out of 750 vertices have any bone bindings at all. This may of course be a problem with the model, but it is being animated correctly in Maya, which confuses me even more.

There is not always a 1:1 mapping. Sometimes meta information are applied directly for the single vertices (e.g. one uv-pair for each vertex, that is you have 750 uv pairs), sometimes they are indexed (you have only 176 weights), sometimes they are incomplete (0 weights are left out ?). Look at the mapping information of the according sub-node.

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