Smoothing issue

I made a relatively simple shape and tried to autosmooth it. Unfortunately some places simply don’t like getting smoothed. I have no idea what’s causing it.
http://xs414.xs.to/xs414/07141/thing.jpg

Whatever is causing it isn’t from welding issues as far as I can tell though.

hi, just tested some smoothing effects, the areas that aren’t smooth need more verts to smooth properly, I would try selecting the faces that need smoothing and subdivide once for a better effect.
Hope this helps. M.A.

With respect to Autosmooth, I believe I read that it only acts on verts that have been Set Smooth.

Have you Removed Doubles?

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Those ridges that refuse to smooth may be caused by internal faces being connected to them. These are called non-manifold faces and are quite easy to make by accident when extruding.