I tested a simple setup with a glass shader in the shader ball and I got this….
Is the shader broken??? why the black shadows inside?
shaderBall broken? Black inside glass
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- Nicolas Heluani
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- Nicolas Heluani
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- Nicolas Heluani
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I posted the solution in another forum but just in case someone wonders into the same pickle:
The Faux caustic seems to help but in reality caustic is a completely different phenomena and it will cause the entire refraction to be exposed (Capture 3). But I found the actual solution under the Mantra Rop in shading setting allowable paths to ALL PATHS!!! I don't understand why on earth this is not so by default! This do raytrace the glass properly (capture4).
Love,
nico.
Updated to latest build and now I have problems with the refraction again even after applying all paths will fill for a bug report.
The Faux caustic seems to help but in reality caustic is a completely different phenomena and it will cause the entire refraction to be exposed (Capture 3). But I found the actual solution under the Mantra Rop in shading setting allowable paths to ALL PATHS!!! I don't understand why on earth this is not so by default! This do raytrace the glass properly (capture4).
Love,
nico.
Updated to latest build and now I have problems with the refraction again even after applying all paths will fill for a bug report.
Edited by Nicolas Heluani - Dec. 13, 2016 15:21:51
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- Nicolas Heluani
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Ok, hopefully this is my final post on this matter…somewhere between build 607 and 673 they change the way faux Caustic works and the problem with over exposure doesn't exist anymore. but the ALL path solution suddenly doesn't work!
The result is the same now and finally I have proper behavior on glass.
I was about to start to build a proper library of materials in mantra….this first step did not make it easy
The result is the same now and finally I have proper behavior on glass.
I was about to start to build a proper library of materials in mantra….this first step did not make it easy
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- anon_user_89151269
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I just found this thread via search-engine; lost a few good hrs fighting with shaders because of this “allowable paths” option. I have a scene where I have an opaque object inside a transparent one.
Maybe I'm misunderstanding something about Mantra, but couldn't these “allowable paths” be managed just by the Limits? Don't want refraction? Set Refract Limit to 0. And so on with the others.
Should that be true, the ongoing “simplify Mantra w/o limiting options” project at SESI, would do good to check on this.
Maybe I'm misunderstanding something about Mantra, but couldn't these “allowable paths” be managed just by the Limits? Don't want refraction? Set Refract Limit to 0. And so on with the others.
Should that be true, the ongoing “simplify Mantra w/o limiting options” project at SESI, would do good to check on this.
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- jsmack
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McNistor
I just found this thread via search-engine; lost a few good hrs fighting with shaders because of this “allowable paths” option. I have a scene where I have an opaque object inside a transparent one.
Maybe I'm misunderstanding something about Mantra, but couldn't these “allowable paths” be managed just by the Limits? Don't want refraction? Set Refract Limit to 0. And so on with the others.
Should that be true, the ongoing “simplify Mantra w/o limiting options” project at SESI, would do good to check on this.
That's not what allowable paths is. Allowable paths is a multiplication of bit masks, meaning that refraction/reflection will only take place if the path starts with a reflection or refraction event. If a path starts with a diffuse event, it will only gather from other diffuse events, unless allow ALL paths is on. Limits have nothing to do with it. You pretty much don't want to use allow all paths unless the path space is extremely wide, otherwise you are simply going to add firefly noise to your renders. Pathtracers simply cannot efficiently trace paths from diffuse events through refraction events to find a small light source. Only other algorithms such as Bi-direction path tracing, Metropolis Light transport, photon mapping, VCM or UPBP can possibly resolve improbable paths such as these in a reasonable time. Of these, mantra only supports photon mapping. You will find the same limitation in every other path tracing renderer. The options are usually labeled differently and some renderers even force the faux caustics on all the time with no option to turn them off.
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- anon_user_89151269
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Thanks jsmack, that's informative.
The point of making Mantra a little easier to set up stands though. I mean, I've never encountered issues with stuff so close to the basics, like a refraction, for the many render engines that I've tested. Some things can surely be done to make life easier for both the inexperienced and the experienced user. I'm wallowing into the generic here, because I'm no Mantra expert, but I hope I got my point across.
The point of making Mantra a little easier to set up stands though. I mean, I've never encountered issues with stuff so close to the basics, like a refraction, for the many render engines that I've tested. Some things can surely be done to make life easier for both the inexperienced and the experienced user. I'm wallowing into the generic here, because I'm no Mantra expert, but I hope I got my point across.
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