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I have imported a mesh (AutoCad DXF) and I'm experiencing strange shading behavior. I've done the following to try and address the problem with no luck:

Recalculate Normals
Remove Doubles
Delete Loose Geometry
Cleared Seam, Sharp, and Bevel Weights

There are no modifiers on the mesh.

The original imported mesh looks fine in smooth shading but I need the mesh to be in quads which causes the shading to mess up as shown in photo. I can add my .blend file but I'm not sure how to do that.

enter image description here


marked as duplicate by cegaton modeling Mar 8 at 16:58

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.


This is generally caused by custom normal data.

Under the Properties Window > Object Data > Geometry Data press Clear Custom Split Normals to get rid of it.

enter image description here


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