Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] Bug Reporting => [Max] Resolved Bugs => Topic started by: GestaltDesign on 2014-12-09, 21:51:22

Title: Geometry artifacts on imported NURBS models
Post by: GestaltDesign on 2014-12-09, 21:51:22
Hi Keymaster,

Having this occur quite regularly on imported geometry, the data originates from Rhino and I have imported as both SAT body objects and meshed obj but still the same issue.
The artifacts do not occur in Vray or Octane when tested, I have attached examples and it mostly occurs on tight radii of surfaces that were split with a detail (when NURBS).

Cheers,

Jon
Title: Re: Geometry artifacts on imported NURBS models
Post by: Ondra on 2014-12-10, 18:24:18
so is that render using SAT objects? If not, I would appreciate the scene ;)
Title: Re: Geometry artifacts on imported NURBS models
Post by: GestaltDesign on 2014-12-11, 12:45:55
Uploaded test scene : 1418298015_CoronaImportTest.zip

Strange, usually the Sat Body objects are most affected (despite playing with different render approx settings) now the OBJ polys are worse in this test.
In the test scene is SAT, Ngon Poly and Tri Poly OBJ.

Cheers,

Jon
Title: Re: Geometry artifacts on imported NURBS models
Post by: GestaltDesign on 2015-01-25, 16:37:58
Hi Keymaster,

Looking forward to the upcoming 1.0 release now and was just wondering if you had an opportunity to look at this issue and if it will be resolved before release?

Many thanks!
Title: Re: Geometry artifacts on imported NURBS models
Post by: Ondra on 2015-01-25, 18:56:59
This is not related to the NURBS input, but to the extremely bad topology of the created objects. There are some extremely elongated triangles causing the troubles.  Repairing the geometry at least a little bit solves the problem for now, I will look for solutions in the future.
Title: Re: Geometry artifacts on imported NURBS models
Post by: GestaltDesign on 2015-01-26, 12:01:37
Yep I see what you mean, even with very clean original geometry the mesh conversion can sometime create a lot of nasty resolutions on trims either internally in Max or from Polys out of Rhino or MOI direct.
I tried to tweak the mesh with render approximation from the body object but I find myself chasing my tail as you solve one corruption and get another.
Unfortunately I am a 100% NURBS guy and know very little on polys so forgive my ignorance. (time to learn!)
Appreciate your effort in finding solutions!
Title: Re: Geometry artifacts on imported NURBS models
Post by: Ludvik Koutny on 2015-06-04, 12:53:28
Escalated to mantis https://corona-renderer.com/bugs/view.php?id=1047 and archived into resolved section.
Title: Re: Geometry artifacts on imported NURBS models
Post by: Ondra on 2015-09-20, 21:29:21
fixed