OBJ import from Maya messes up Normals in Blender

Hi there… I had been trying to achieve a certain Boolean’ed out model in Blender, but it kept not working, so I did it in Maya, then exported it as an .obj file and imported that file into Blender. The model comes in cleanly, except it is faceted where it was previously smooth. Therefore, I used the Set Smooth option in Blender, but when I do this, it messes up the Normals along the edges where the faces don’t line up right (as a result of the Boolean operations). Is there something I can do in the export/import stage to correct this? Or is there a way to do this in Blender to fix only certain Normals?

This is one of the most frustrating issues I’ve run into in 3D programs. If there’s not a fix… is there a work-around?


well the first thing to try is (in edit mode) hit ctrl-n to recalculate normals outside. This works for some meshes…I don’t understand why it doesn’t work sometimes though:confused:.

If that doesn’t work, you can turn on “Draw normals” while in edit mode in the editing panel (F9). This will display your normals, and you can then select the culprits and hit W-Flip normals to correct them. I find it useful, particularily in complex meshes, to make sure “Limit selection to visible” is turned on (bottom of 3D window header, looks like an isometric cube beside the vert/edge/face mode buttons. (in edit mode).

Well, try what dschnell recommended, and if that doesn’t work open the model in Maya, and in your view port under: >>Shading >> Select “Back Face culling” this will make it so you can only see the fronts of your normals, and will make them invisible from the back. You will now be able to see if your model has any reversed normals in it.
If it does, simple select the reversed faces and go to:>>Normals >>Reverse.

If this is not the problem then i’m going to say that Booleans are to blame.
If i remember correctly Blender doesn’t support 5 or more sided faces, whereas maya does, so this could be your problem. Make sure your model is in all Quads or all Tris.

If you still can’t fix the problem, then try posting a screen grab of the prob, and see if that helps us to identify the problem.