Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] Bug Reporting => [Max] Resolved Bugs => Topic started by: ecximer on 2013-02-13, 15:03:30

Title: Glowing corners
Post by: ecximer on 2013-02-13, 15:03:30

Glowing corners in single-sided geometry.
When added Shell modifier glow disappears.

Title: Re: Glowing corners
Post by: maru on 2013-02-13, 15:05:13

Yes, I noticed this too. Flipping normals doesn't seem to change anything, so maybe it's path tracing related.

Title: Re: Glowing corners
Post by: Ondra on 2013-02-13, 16:08:38

Looks like self-intersection/light leaks. Tesselating the wall polygons should help a little. Isn't the scene for example far from origin?

Title: Re: Glowing corners
Post by: ecximer on 2013-02-13, 20:33:58

No, the scene is located in the center.
Tessellate not try, but do not want to add extra polygons to an overloaded and so the scene.

Title: Re: Glowing corners
Post by: iliyang on 2013-02-13, 21:55:33

Looks like a too large ray offset epsilon to me, which makes rays escape the scene and hit the background. First, make sure that the triangles at the corner share the same vertices. Then try enlarging the two walls on the corner slightly so that they intersect each other. This should fix the problem.

Title: Re: Glowing corners
Post by: Ondra on 2013-02-13, 22:51:18

Quote from: iliyang on 2013-02-13, 21:55:33

Looks like a too large ray offset epsilon to me, which makes rays escape the scene and hit the background. First, make sure that the triangles at the corner share the same vertices. Then try enlarging the two walls on the corner slightly so that they intersect each other. This should fix the problem.

Or the epsilon is too small, and the secondary ray is classified as hitting the other triangle in the corner from outside the scene (so next ray is bounced into the environment). If I enlarge the epsilon, i get leaks, if I decrease it, i get self-intersections. Refer to this post for summary of my thoughs on the matter: http://forum.corona-renderer.com/index.php/topic,401.msg2874.html#msg2874

Title: Re: Glowing corners
Post by: ecximer on 2013-02-14, 07:09:49

Ok. I understood that this error not an error is a feature. :)

Title: Re: Glowing corners
Post by: Ludvik Koutny on 2013-02-14, 08:29:16

Quote from: ecximer on 2013-02-14, 07:09:49

Ok. I understood that this error not an error is a feature. :)

Yes, this is an error, but not easy to fix ;)

Title: Re: Glowing corners
Post by: Stan_But on 2013-03-22, 17:44:57

i found same bug with curtain - helped only "shell" too.
But curtain was with self-intersection polygons and i thought that cause in bad modeling

sorry for bad english (c) ^^

Title: Re: Glowing corners
Post by: Ondra on 2013-03-23, 01:34:20

http://forum.corona-renderer.com/index.php/topic,401.msg2874.html#msg2874

I'll take look at it, upload any scene that has such problem

Title: Re: Glowing corners
Post by: Stan_But on 2013-03-23, 21:39:16

two image with example and scene (max 2012 corona alpha 4) in attachment

Title: Re: Glowing corners
Post by: Ondra on 2013-09-14, 18:55:45

Duplicate of a mantis entry: http://corona-renderer.com/bugs/view.php?id=133