Can Blender "un-smooth" a mesh?

Question

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?

related: if you receive a blender model which has smooth shade enabled, how can you undo this? — juFo, Sep 24 '14 at 06:57

Daniel · Accepted Answer · 2013-05-30T14:04:05.940

19

Yes. Use the smooth modifier with a negative factor.

Smooth modifier

edited May 30 '13 at 14:04

answered May 23 '13 at 01:25

Daniel

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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? – nanofarad May 23 '13 at 01:41
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. – Daniel May 23 '13 at 01:44
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This is not the case. Compare before and after. Opening them in different browser tabs and switching quickly shows the effect. – nanofarad May 23 '13 at 01:48
Nice find. Good to know. – Daniel May 23 '13 at 01:48

score 11 · Answer 2 · answered May 24 '13 at 06:18

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.

score 9 · Answer 3 · edited May 24 '13 at 05:10

9

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

edited May 24 '13 at 05:10

Daniel

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answered May 23 '13 at 01:52

nanofarad

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come on! rerender this with suzanne fitting the window and lit up with more ambient lighting, so much grey..so little suzanne.. – zeffii May 24 '13 at 08:13
@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. – nanofarad May 24 '13 at 10:29
Would be great if you could find the time, @ ping me in case. I'd like to upvote. – Leander May 14 '19 at 12:05
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@Leander added to todo list; hopefully will have time this week at some point. – nanofarad May 14 '19 at 12:26

score 4 · Answer 4 · answered May 30 '13 at 11:06

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

answered May 30 '13 at 11:06

howardt

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score 3 · Answer 5 · edited Oct 20 '20 at 12:23

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

edited Oct 20 '20 at 12:23

Timaroberts

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answered Jun 09 '13 at 21:48

user383

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Or maybe the remesh. – Róbert László Páli Jun 18 '13 at 09:03
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. – CharlesL Jun 23 '13 at 23:50

score 2 · Answer 6 · answered Jun 09 '13 at 22:02

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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.}

answered Jun 09 '13 at 22:02

wchargin

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Left is the original, is it not? – nanofarad Jun 15 '13 at 23:09
Yeah, the top of the nose and the top of the mouth are the only real giveaways i see. – Weaver Nov 27 '14 at 22:08

Can Blender "un-smooth" a mesh?

6 Answers6