Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] Bug Reporting => [Max] Resolved Bugs => Topic started by: jjduncs on 2014-10-13, 10:45:22

Title: Shadow catcher "For Compositing" mode introducing noise.
Post by: jjduncs on 2014-10-13, 10:45:22: I'm wanting to use the 'for compositing' mode with the shadow catcher mtl. Ive got the override visibility set to black (backplate bitmap unchecked).

The issue I am getting is that using this mode, it is producing more noise than when the alpha mode is on 'always solid' and the backplate is in the direct visibility override.

The left image has shadow catcher with 'for compositing' alpha mode and you can see the extra noise/fireflies that are appearing. The right image is when alpha mode is 'always solid' and the backplate is in the visibility override.

Both renders are after about 7 passes.

A bit of the backplate is showing on the left image and Im assuming this is just from reflected GI from the 3d objects. With the alpha mask this is all erased so I don't think that is part of the issue.

Not sure if this constitutes a bug but it is definitely the alpha mode in the shadow catcher that is causing this difference.
Title: Re: Shadow catcher "For Compositing" mode introducing noise.
Post by: maru on 2015-02-09, 13:37:05: [this is not an answer, just a note]
more details are in this thread: https://forum.corona-renderer.com/index.php/topic,5242.msg37776.html#msg37776
Looks like it was caused by pt+hd. I was unable to recreate it. UHD cache possibly fixed this. (?)
Title: Re: Shadow catcher "For Compositing" mode introducing noise.
Post by: Ondra on 2015-02-13, 21:19:56: That is fairly unconverged image, and there are similar fireflies in the second image, just more scattered. Does the noise eventually goes away?

I could take a look at the scene if you wanted
Title: Re: Shadow catcher "For Compositing" mode introducing noise.
Post by: jjduncs on 2015-03-17, 14:02:14: It's an old scene now but it was the HD Cache that was causing it. Noise didn't go away after cooking for ages, but on PT + PT mode it was fine.

Cheers
Title: Re: Shadow catcher "For Compositing" mode introducing noise.
Post by: Ondra on 2015-03-17, 14:12:51: it should still work with caching - if there is still problem when using UHD cache (the new cache in Corona 1.0), could you send me the scene so I can investigate?
Title: Re: Shadow catcher "For Compositing" mode introducing noise.
Post by: jjduncs on 2015-03-17, 16:28:30: Yep no worries I'll have a crack at it tomorrow.
Title: Re: Shadow catcher "For Compositing" mode introducing noise.
Post by: Ludvik Koutny on 2015-06-04, 17:38:33: Any updates on this? Or can i close the report?
Title: Re: Shadow catcher "For Compositing" mode introducing noise.
Post by: Ludvik Koutny on 2015-06-10, 12:18:56: Inactive topic, moving to resolved. If you still experience the issue, feel free to create new bug report.