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[BUG] SubDiv Artifacts

Posted: Thu Aug 20, 2009 3:14 pm
by Zom-B
A simple low poly sphere get 5 subdivides with smoothing to smooth the mesh during subdiv.
Wrapping U/V is needed to get the texture to work probably, but some small artifacts are still there
See attached files (low res texture included)

The artifacts are in the area where texture artifacts happen when NOT using U/V wrapping...

Without smoothing (that is the point here!) I also get artifacts... but different ones!
bug.jpg
bug.jpg (226.27 KiB) Viewed 2887 times
subdiv.zip
(297.63 KiB) Downloaded 145 times

Re: [BUG] SubDiv Artifacts

Posted: Fri Aug 21, 2009 2:41 am
by Whaat
I have got strange results using subdivision + smoothing without even using textures. The resulting mesh is not smooth. Try subdividing and smoothing a wineglass model and you'll see what I mean.

Re: [BUG] SubDiv Artifacts

Posted: Fri Aug 21, 2009 2:50 am
by Zom-B
yes, the texture is only a help to show the quite nice U/V Wrap of the texture.... besides of the artifacts...

Also very annoying are the artifacts generated on closeup to subdiv meshes when "View Dependent" is checked! This should really have a threshold to the edges of the camera or even have a option to combine with backface culling...

Re: [BUG] SubDiv Artifacts

Posted: Tue Jan 19, 2010 11:39 pm
by Zom-B
I would like to take this thread back from the death & forgotten.

With Indigo 2.2 stable smoothing & subdiv still generates Texture chaos, here 3 images:
subdiv_no_smoothing.jpg
Subdiv, but no smoothing
subdiv_no_smoothing.jpg (109.65 KiB) Viewed 2690 times
subdiv_wrap.jpg
Subdiv with smoothing & wrap U+V
subdiv_wrap.jpg (122.93 KiB) Viewed 2691 times
subdiv_no_wrap.jpg
Subdiv with smoothing & no wrap
subdiv_no_wrap.jpg (131.63 KiB) Viewed 2696 times

Re: [BUG] SubDiv Artifacts

Posted: Wed Jan 20, 2010 12:21 am
by pixie
Zom-B wrote:I would like to take this thread back from the death & forgotten.

With Indigo 2.2 stable smoothing & subdiv still generates Texture chaos, here 3 images:
subdiv_no_smoothing.jpg
subdiv_wrap.jpg
subdiv_no_wrap.jpg
So now I understand it, I had the same issue a few time ago. It was so strange I didn't knew where to begin. I had some instantiated scene and it was all messed up, just like the warp image.

Re: [BUG] SubDiv Artifacts

Posted: Wed Jan 20, 2010 6:50 am
by CTZn
I'm adding my weight to bump the thread, thanks Zom-B !

I'm not sure what is causing this in Indigo's smoothing approach, perhaps a simple bug ? Or merging should occur also for UVs (welding) ? Or UVs should (not ? optionally ?) be smoothed along with mesh ?

In case of doubt, perhaps deconstructing the meshing/UVing operations into more options would help debug ? I'm fond to explore that :D

Big smoothing issue indeed, reducing smoothing usage to non-textured objects. Meanwhile subdivide the mesh externally and use displacement for details only (subdivisions=ON, Smoothing=OFF).

Re: [BUG] SubDiv Artifacts

Posted: Wed Jan 20, 2010 10:19 am
by OnoSendai
Hi Zom-B,
the whole subdivision code needs a thorough going over, to make it faster, as well as to fix the texturing artifacts you mentioned, as well as some smoothing issues. I'll try and find time for this soon.

Re: [BUG] SubDiv Artifacts

Posted: Wed Jan 20, 2010 10:30 am
by Zom-B
Super awesome news master Ono :!:

Thanks in advance, the whole subdiv smoothing bug is a real showstopper in my workflow :cry:

I'm also looking forward to multithreaded subdiv, or even a GPU based approach...

Re: [BUG] SubDiv Artifacts

Posted: Fri Jan 22, 2010 2:06 am
by benn
Me and Yves will take a look at this for 2.4. Let us at the core. :)