Often with imported OBJ meshes I noticed that some seemingly random vertices are surrounded in dark blotches and sometimes adjacent ones are pale. Yet all the readable characteristics are identical to a normal vert angle stats. So why when I was messing around I unchecked Auto Smooth did theses anomalies go away?

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  • 1
    $\begingroup$ Could you provide a screenshot of the mesh with auto smooth on and then off please? $\endgroup$
    – HoltH
    Aug 9, 2016 at 13:01
  • $\begingroup$ Auto smooth will create strange shading when dealing with non planar geometry (specially ngons), or when the amount of vertices is too low to achieve proper curvature of a set of faces. Please upload an image of your particular issue. $\endgroup$
    – user1853
    Aug 9, 2016 at 16:03

1 Answer 1


I sometimes had effects like this because custom split normals data was imported and got distorted somehow. AutoSmooth only seems to work reliably if this data is deleted, try the button in the Mesh Data section to clear custom split normals data:

clear custom split normals data


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