Blender, Exporting to Collada, Assimp and Normal Maps

Question

I have a simple model that uses a diffuse and a normal map - in this case just two textures applied to the same material, where for the normal map I uncheck all the options in the "Influence" section in Blender and check the option for "Normals". Inside Blender the normal map is used correctly, but when I export the file to collada and try to load it with OpenAssimp, the normal map doesn't show up in the material.

Also, the Collada file doesn't seem to mark the normal map as something special, it's just listed as another image under (there's no reference to it being a normal map, and there is no bump effect in library_effects).

Do I need to activate some special option in blender to make sure the normal shows up in the collada file?

Notes: AssimpView doesn't load the normal map either, but when I export as 3DS it shows the normal map correctly - too bad I can't use 3DS since it doesn't support bones.

Answer 1

Open the .dae file in a text editor. Search for:

<bump>  

If its just called <bump>, change it to:

<bump bumptype="NORMALMAP">  

Then, below your material type, and above </technique>, paste the following and replace with your normal texture name. In context, it should look like this:

</phong>
<extra>
  <technique profile="FCOLLADA">
    <bump bumptype="NORMALMAP">
      <texture texture="example_Normal_jpg-sampler" texcoord="UVMap"/>
    </bump>
  </technique>
</extra>
</technique>

:)