When a mesh is smoothed, every selected vertex is moved towards the average position of its neighbors. Is there a way to do the opposite, given a mesh with bumps, curves and corners, to move selected vertices by small amounts opposite of what mesh smoothing would do?
Yes. Use the smooth modifier with a negative factor.
An alternative method to reverse an operation is to add 2 shape keys, enter editmode with with a non-basis shape, edit the mesh (smooth it for example), exit editmode, then slide the shape key to a negative value you can then optionally apply it to the base mesh.
Unsmoothing with a negative modifier is sufficient for a roughening effect, but not to fully undo a smoothing operation. To test this, I rendered Suzanne and smoothed the mesh(factor 1.0), applied the modifier, and then unsmoothed with factor -1.0.
Another thing to try is the Laplacian Smooth modifier with a negative factor.
If you're looking to make a model more low-poly, then try using the Decimate modifier.
If you're looking to reverse the Subdivision Surface modifier, try the Decimate Modifier on Un-Subdivide mode. I find that you should usually double the subsurf level in the decimate modifier.
One of these Suzannes has been subdivided twice and then un-subdivided four times with the Decimate modifier. How well do you know your Suzannes? Which is which?
Also take a look at a smooth-shaded version:
Original face count: 500; processed face count: 699.
protected by iKlsR♦ Jun 13 '13 at 12:14
Thank you for your interest in this question.
Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).
Would you like to answer one of these unanswered questions instead?