15
$\begingroup$

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?

$\endgroup$
  • $\begingroup$ related: if you receive a blender model which has smooth shade enabled, how can you undo this? $\endgroup$ – juFo Sep 24 '14 at 6:57
18
$\begingroup$

Yes. Use the smooth modifier with a negative factor.

Smooth modifier

$\endgroup$
  • $\begingroup$ Is the smoothing process perfectly reversible(not considering floating-point error), or will unsmoothing a mesh by the same factor as it was smoothed produce a different mesh? $\endgroup$ – hexafraction May 23 '13 at 1:41
  • $\begingroup$ It appears like it is. I'm not sure, but I tested it with Suzanne, and it appeared to get back to its original geometry. $\endgroup$ – Daniel Pendergast May 23 '13 at 1:44
  • 1
    $\begingroup$ This is not the case. Compare before and after. Opening them in different browser tabs and switching quickly shows the effect. $\endgroup$ – hexafraction May 23 '13 at 1:48
  • $\begingroup$ Nice find. Good to know. $\endgroup$ – Daniel Pendergast May 23 '13 at 1:48
11
$\begingroup$

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.

$\endgroup$
9
$\begingroup$

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.

animated gif

$\endgroup$
  • 8
    $\begingroup$ come on! rerender this with suzanne fitting the window and lit up with more ambient lighting, so much grey..so little suzanne.. $\endgroup$ – zeffii May 24 '13 at 8:13
  • $\begingroup$ @zeffii I was short on time so I basically threw this in a scene with the defaults. When I have some time tomorrow I'll make a better image(animated as a GIF) that shows this. $\endgroup$ – hexafraction May 24 '13 at 10:29
  • $\begingroup$ Would be great if you could find the time, @ ping me in case. I'd like to upvote. $\endgroup$ – Leander May 14 at 12:05
  • 1
    $\begingroup$ @Leander added to todo list; hopefully will have time this week at some point. $\endgroup$ – hexafraction May 14 at 12:26
4
$\begingroup$

Another thing to try is the Laplacian Smooth modifier with a negative factor.

$\endgroup$
3
$\begingroup$

If you're looking to make a model more low-poly, then try using the Decimate modifier.

$\endgroup$
  • $\begingroup$ Or maybe the remesh. $\endgroup$ – Róbert László Páli Jun 18 '13 at 9:03
  • $\begingroup$ Please try to answer the question asked. Your answering how to un-subsurf a mesh. The question is asking how to use the smooth tool in reverse. $\endgroup$ – CharlesL Jun 23 '13 at 23:50
2
$\begingroup$

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?

Two Suzanne meshes – which is the original?

Also take a look at a smooth-shaded version:

Smooth version of above image

Original face count: 500; processed face count: 699.

$\endgroup$
  • 2
    $\begingroup$ Left is the original, is it not? $\endgroup$ – hexafraction Jun 15 '13 at 23:09
  • $\begingroup$ Yeah, the top of the nose and the top of the mouth are the only real giveaways i see. $\endgroup$ – StarWeaver Nov 27 '14 at 22:08

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?

Not the answer you're looking for? Browse other questions tagged or ask your own question.