# Noise in reflected refraction. **URL:** \ **Category:** Issues\ **Created:** [October 24, 2014, 1:26pm UTC](https://forums.chaos.com/t/noise-in-reflected-refraction/129262 "2014-10-24T13:26:40Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![maru](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/maru/32/15975_2.png) [@maru](https://forums.chaos.com/u/maru)\ **Post date:** [October 24, 2014, 1:26pm UTC](https://forums.chaos.com/t/noise-in-reflected-refraction/129262/1 "2014-10-24T13:26:40Z")
Build timestamp: Oct 14 2014 02:21:33 I’m not sure if this hasn’t been reported yet, please let me know. When there is a glossy reflection of a light seen through a solid glass object, the reflection gets very noisy and the noise does not go away at all. The problem can be observed in this thread: > **[need to create realistic glass, but how??](https://forums.chaos.com/index.php/topic,5325.0.html)** > > Dear all, i want to create realistic glass like the pictures i attached (photo). how to setup the glass material with green color on the edge and clear on the surface? do i have to create multimaterial, clear for the surface & green for the edge..??... I didn’t manage to improve it by changing glass parameters, different sampling settings, different light settings, changing from GGX to AS. This also happens to objects with Corona Light mtl (but only if it “emits light”), but odd enough the reflection is more uniform when using CoronaMtl with self-illumination on. Maybe it’s a hint? This does NOT happen to **refracted reflections**. It also looks ok if reflective material has no glossiness. Sorry for being so random but I’m in a little hurry. Images: r1, r1a - no reflectivity for ground plane r2, r2a - glossy reflectivity turned on for ground plane v1, v2 - different views of the problem refract1 - refracted reflection SE - self-illumination in CoronaMtl ![r1.jpg](https://europe1.discourse-cdn.com/chaosprd/original/3X/5/4/54b548832c160a1c01b16be2f52c30808d706623.jpeg) ![r1a.jpg](https://europe1.discourse-cdn.com/chaosprd/original/3X/f/1/f19841d8543268f37cc7a5b07e267c2f5b921fe0.jpeg) ![r2.jpg](https://europe1.discourse-cdn.com/chaosprd/original/3X/e/6/e6de2869c357a7acaa2b8d280f613910373c3408.jpeg) ![r2a.jpg](https://europe1.discourse-cdn.com/chaosprd/original/3X/e/a/eadda9d101ca471e0fddae59afdece19a0452845.jpeg) ![refract1.jpg](https://europe1.discourse-cdn.com/chaosprd/original/3X/8/b/8b6aaeda8bc88ee38d7e9986869cbe655deb27a6.jpeg) ![SE.jpg](https://europe1.discourse-cdn.com/chaosprd/original/3X/a/4/a4d545c65a1b6d629d60443bcebfa451fdd20172.jpeg) ![v1.jpg](https://europe1.discourse-cdn.com/chaosprd/original/3X/2/7/27739080d9136cb4c433e1d2836dffd10698c30a.jpeg) ![v2.jpg](https://europe1.discourse-cdn.com/chaosprd/original/3X/a/b/ab0cbcd0f4940bb4794e71bdb61ec771cdca10cc.jpeg) ---
**Author:** ![maru](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/maru/32/15975_2.png) [@maru](https://forums.chaos.com/u/maru)\ **Post date:** [October 25, 2014, 3:28pm UTC](https://forums.chaos.com/t/noise-in-reflected-refraction/129262/2 "2014-10-25T15:28:29Z")
hello 😕 ---
**Author:** ![maru](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/maru/32/15975_2.png) [@maru](https://forums.chaos.com/u/maru)\ **Post date:** [October 25, 2014, 6:20pm UTC](https://forums.chaos.com/t/noise-in-reflected-refraction/129262/3 "2014-10-25T18:20:36Z")
here is a bit more “real world” example, light and sun+sky ![42pass.jpg](https://europe1.discourse-cdn.com/chaosprd/original/3X/c/d/cdcbc521c8a600b12529c8f88d4ce8f80bceabb7.jpeg) ![42pass_sunsky.jpg](https://europe1.discourse-cdn.com/chaosprd/original/3X/4/b/4bc162dbbc87c822bfc0d68a5dce5bc28a049008.jpeg) ---
**Author:** ![lacilaci](https://avatars.discourse-cdn.com/v4/letter/l/48db29/32.png) [@lacilaci](https://forums.chaos.com/u/lacilaci)\ **Post date:** [October 26, 2014, 9:06am UTC](https://forums.chaos.com/t/noise-in-reflected-refraction/129262/4 "2014-10-26T09:06:15Z")
You can try to disable “visible in refractions” on your light source, or lowering MSI to a very low value (1?), or try using BiDir.. I would try to avoid this situation from happening (refracted light source being reflected on rough surface) Not sure if bug or just a standard behavior though… ---
**Author:** ![maru](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/maru/32/15975_2.png) [@maru](https://forums.chaos.com/u/maru)\ **Post date:** [October 26, 2014, 3:40pm UTC](https://forums.chaos.com/t/noise-in-reflected-refraction/129262/5 "2014-10-26T15:40:20Z")
This may be really hard to avoid in normal work! Like a glass of water standing on a table… ---
**Author:** ![leonel20](https://avatars.discourse-cdn.com/v4/letter/l/77aa72/32.png) [@leonel20](https://forums.chaos.com/u/leonel20)\ **Post date:** [November 1, 2014, 5:56am UTC](https://forums.chaos.com/t/noise-in-reflected-refraction/129262/6 "2014-11-01T05:56:35Z")
are there someone that would like to explain this? just like lacilaci said, is it a bug or just another kind of standard behavior?? ---
**Author:** ![maru](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/maru/32/15975_2.png) [@maru](https://forums.chaos.com/u/maru)\ **Post date:** [November 1, 2014, 8:40am UTC](https://forums.chaos.com/t/noise-in-reflected-refraction/129262/7 "2014-11-01T08:40:39Z")
Yeah, I’m surprised there is so little attention to this topic. Maybe I’m doing something wrong? ---
**Author:** ![Ondra\_1](https://avatars.discourse-cdn.com/v4/letter/o/50afbb/32.png) [@Ondra\_1](https://forums.chaos.com/u/Ondra_1)\ **Post date:** [November 3, 2014, 4:48pm UTC](https://forums.chaos.com/t/noise-in-reflected-refraction/129262/8 "2014-11-03T16:48:59Z")
This is only another instance of the hybrid glass + reflections bug. It was already reported, changing the glass mode to anything but thin-off, caustics-off helps. There is currently no other solution ---
**Author:** ![maru](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/maru/32/15975_2.png) [@maru](https://forums.chaos.com/u/maru)\ **Post date:** [November 3, 2014, 7:41pm UTC](https://forums.chaos.com/t/noise-in-reflected-refraction/129262/9 "2014-11-03T19:41:44Z")
Ok, thanks for the reply. I think this is a really serious flaw. ---
**Author:** ![leonel20](https://avatars.discourse-cdn.com/v4/letter/l/77aa72/32.png) [@leonel20](https://forums.chaos.com/u/leonel20)\ **Post date:** [November 4, 2014, 1:47am UTC](https://forums.chaos.com/t/noise-in-reflected-refraction/129262/10 "2014-11-04T01:47:07Z")
> [@Keymaster](#): > > This is only another instance of the hybrid glass + reflections bug what is “hybrid glas”?? ---
**Author:** ![maru](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/maru/32/15975_2.png) [@maru](https://forums.chaos.com/u/maru)\ **Post date:** [November 4, 2014, 9:10am UTC](https://forums.chaos.com/t/noise-in-reflected-refraction/129262/11 "2014-11-04T09:10:30Z")
It’s solid glass with no caustics (transparent shadows). ---
**Author:** ![leonel20](https://avatars.discourse-cdn.com/v4/letter/l/77aa72/32.png) [@leonel20](https://forums.chaos.com/u/leonel20)\ **Post date:** [November 4, 2014, 9:22am UTC](https://forums.chaos.com/t/noise-in-reflected-refraction/129262/12 "2014-11-04T09:22:42Z")
oh, so it’s just a glass that actually has caustic (in real world), and if the caustic effect removed & replaced with transparent shadows, then it named hybrid glass. ok i got it. thanx