Chaos Corona Forum
Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: RobH2 on 2018-07-27, 18:17:28
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I have an object behind glass. I need to render a mask of it. The transparent material obscures the mask and if I render the mask with the glass turned off, the mask is not in the correct location due to refraction.
How can it pull a mask from something behind glass while leaving the glass enabled?
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Currently you can't. Simply that. Vote for
"Refraction/Reflection working with masking render elements (CMasking_Mask,CTexmap, etc...)"
here:
https://forum.corona-renderer.com/index.php?topic=96.0
if you need it desperately.
Good Luck
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Good enough. I'll vote.
Well, we all think that everything we need is "desperate" don't we...lol...? I'll render the mask in VRay I guess. I think it can do it.
Thanks for the fast response.
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or hide the glass and re render only masks. I dreaded this workflow but surprisingly was very fast for an animation I did
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You don't get a refractive mask doing so. Depending on the (glass) object you only get some approximation but usually just a wrong mask.
Good Luck
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yes sorry, I misread the initial post
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Smartass alert here but can't you disable all lights, set the glass reflection to zero, set the object that you need a mask of to self illumination 1/white and render that? Not a direct solution but maybe a viable workaround.
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Interesting hack! Now we have shadowcatcher workaround for opacity masks and self illu for refraction - and a horrible workflow :) But for that one mask quickly needed, why not.
Good Luck
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Yeah it's not very elegant but will probably work, I've used this setup on a few occasions. Forgot to specify that you'd probably need to use a LightMtl because you need to make the object not emit any light.
If you need the mask for reflections too you need to keep reflections enabled for the glass material.
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nice!
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I just had to do a similar trick that pokoy used. Put a Rayswitcher on the object behind the glass and have only the 'refract override' set to a self illuminated RG or B color. This will stop the self-illum from kicking out any GI. Put a flat black material on everything except the glass and refracted object. I'd save a scene state before doing this.
Aside from all that, is it really that hard to implement this or is it just not a high priority?
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Same problem for me here.
I'm working on a commercial with a fish in an aquarium. It is practically impossible to use the render elements for post-production because of the refraction of the aquarium glass.
JULIEN
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What if you set the aquarium glass object to "not visible to camera"?
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i found this...
dont know if it helps.
https://coronarenderer.freshdesk.com/support/solutions/articles/5000529357-how-to-make-an-object-invisible-in-masks-render-elements-
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Wow, I never knew about that. Thank you!
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i found this...
dont know if it helps.
https://coronarenderer.freshdesk.com/support/solutions/articles/5000529357-how-to-make-an-object-invisible-in-masks-render-elements-
Wow, I never knew about that. Thank you!
That still won't allow you to render a mask which is affected by refraction.
We have this logged in our internal tracker as one of the top 10 feature requests from the users.
(internal id=291805959)
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Coming up against this limitation of Corona right now, albeit with reflections instead of refractions. This is really a killer for me given the way I'm using Corona. I know this has been asked for for years, any chance we'll see this implemented soon? I'm trying to figure out workarounds so I don't have to switch to Vray.
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I have to say, "Wow" on this too. I've been trying for a year to find a way to render masks behind glass and decided to read today to see if anyone ever solved it in a manner that didn't take too may extra contortions. I don't know when this switch showed up but "Visible in masks" is my new BFF.