Chaos Corona Forum
Chaos Corona for Cinema 4D => [C4D] General Discussion => Topic started by: mitchino on 2018-05-25, 21:39:53
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I'm putting together a scene of an object on the floor of a dark enclosed room with a small window. I have an area light outside shining through the window and backlighting the object. I have set up a volume material and put it in the Scene Environment slot of the render settings.
It's working ok but I have a few questions.
How do I make the light rays/shafts of light brighter but keep the room fairly dark and keep the same exposure on the object?
I have another area light for a bit of front fill on the object, how do I stop that from having light rays too?
Can I render out the rays as a separate render pass?
How do I reduce the noise in the render? Do I just have to let it cook and accept long render times?
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I'll take a crack at this from my personal experience - others or the developers may have better answers:
I'm putting together a scene of an object on the floor of a dark enclosed room with a small window. I have an area light outside shining through the window and backlighting the object. I have set up a volume material and put it in the Scene Environment slot of the render settings.
It's working ok but I have a few questions.
How do I make the light rays/shafts of light brighter but keep the room fairly dark and keep the same exposure on the object?
--You can use exclude for that light, or better, set up two lights - one for the volumetrics only and one to light the space.
I have another area light for a bit of front fill on the object, how do I stop that from having light rays too?
--No way to do that as far as I know. This kills me a lot. Redshift lets you control the volumterics per light which is really nice. I've only had luck by backing that light further away from the objects. Hack.
Can I render out the rays as a separate render pass?
--There is a Volumterics option in multipass, though I haven't used it. I tend to do a separate render where I Material override everything with Matte Pure Black and then comp the rays together in post. Again - I'm a hack :)
How do I reduce the noise in the render? Do I just have to let it cook and accept long render times?
--Yup....
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For the last question:
Increase the light samples multiplier
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For the last question:
Increase the light samples multiplier
It's defaulted to 2. I've tried played around with increasing this, but not seeing much of a difference. What do you think a decent setting for this is? I guess I'm wondering if you mean take it to 4 or if you mean take it to like 512....
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There was another thread where one had one light(directed) a cube with a volumetric material. The perfect example to test the ray noise.
Bumping up the value to 4 had an obvious visually better result than 2. the render time didn't increase by much. I tried up to 32 which also gave much better results than 4 but the render time was more than doubled.
I'll look for the thread later but meanwhile: increasing the LSM helps a lot to clear volumetric noise but at too high values it takes way too long. A max value of 10 should not be exceeded. (according to my tests)
Found it! (https://forum.corona-renderer.com/index.php?topic=19377.msg121162#msg121162)
7 passes each. left, LSM 2 / right, LSM 8.
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=19377.0;attach=79964;image)
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Awesome! Thanks for the info.