Hi, I am having problems rendering both Transmission and Reflection simultaneously in Glass materials. It is either only one or the other.
Here is the setup:
Green Area Lights pointing perpendicularly to the Glass Object from some distance and so was the viewing direction and expect maximum reflection.
Red Laser Lights above and entering at a angle toward the Glass Object with Homogeneous Volume Inside and expect Transmission to any viewing direction.
However these are what I got:
Only Reflected Green Area Lights from Glass Object is visible while a segment of Red Laser Lights inside the Glass Object cannot be seen when Visible to Camera is enabled.
Only Transmitted Red Laser Lights is visible while reflected Green Area Lights cannot be seen when Visible to Camera is disabled.
Are there other settings or fine tuning to make to allow for both to show up please???
Glass Object Ray Tracing Problem
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Please upload a testscene that allows developers to reproduce the problem, and attach some images.
Please upload a testscene that allows developers to reproduce the problem, and attach some images.
Glass Object Ray Tracing Problem
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- Glass Ray Tracing.blend
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Re: Glass Object Ray Tracing Problem
p.s.
Here is another better illustration with global illumination.
Glass Cube Object - Visible to Camera Unchecked
Glass Cube Object - Visible to Camera Unchecked Volumetric lights are lost and maybe as well Torus Object bounce light reflections from Matte Plane Object underneath.
Here is another better illustration with global illumination.
Glass Cube Object - Visible to Camera Unchecked
Glass Cube Object - Visible to Camera Unchecked Volumetric lights are lost and maybe as well Torus Object bounce light reflections from Matte Plane Object underneath.
- Attachments
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- Glass Ray Tracing 2.blend
- (1.29 MiB) Downloaded 120 times
Re: Glass Object Ray Tracing Problem
P.S.
Animated GIF (please click on the image)
Animated GIF (please click on the image)
Re: Glass Object Ray Tracing Problem
What you are seeing is a classic case of "SDS" caustics (spcular-diffuse-specular), which are inherently difficult to render. With a laser light, even impossible.
The homogeneous volume scattering is diffuse. Glass is specular, and both entering and exiting the cube are counted as spearate events. Hence Entering -> scattering -> exiting = SDS
When you set invisible to camera, it seems that the glass surface (towards the camera) is set to a null surface, which removes the specular component there - making the laser visible. At the same time, this is true for the green reflection, which disappears when the reflecting surface is invisible.
The only setting I can think of that might(!) help is the caustics cache.
The homogeneous volume scattering is diffuse. Glass is specular, and both entering and exiting the cube are counted as spearate events. Hence Entering -> scattering -> exiting = SDS
When you set invisible to camera, it seems that the glass surface (towards the camera) is set to a null surface, which removes the specular component there - making the laser visible. At the same time, this is true for the green reflection, which disappears when the reflecting surface is invisible.
The only setting I can think of that might(!) help is the caustics cache.
Re: Glass Object Ray Tracing Problem
CodeHD wrote: ↑Mon Apr 05, 2021 6:25 pm What you are seeing is a classic case of "SDS" caustics (spcular-diffuse-specular), which are inherently difficult to render. With a laser light, even impossible.
The homogeneous volume scattering is diffuse. Glass is specular, and both entering and exiting the cube are counted as spearate events. Hence Entering -> scattering -> exiting = SDS
When you set invisible to camera, it seems that the glass surface (towards the camera) is set to a null surface, which removes the specular component there - making the laser visible. At the same time, this is true for the green reflection, which disappears when the reflecting surface is invisible.
The only setting I can think of that might(!) help is the caustics cache.
Thanks Recalled BRDF function and light rays integration. Caustic illuminated diffused surfaces (refracted and internally reflected light rays from glass material upon the diffused microscopic particles ) and then bouncing its bright lit rays but only from small surface area to another specular surface (glass cube front face). The very finite sampling points due to limited computing power plus the former so no wonder they turned up invisible on the camera despite knowing it should be there I even initially thought BlendLuxCore erroneously make the Glass Object opaque to Volumetric Lights so they cannot be seen by the Camera.
I tested it with another specular Material that is Mirror and fortunately the results are still the same to prove the SDS issue.
Also removed the Glass Cube Object Front Face so the Laser will be visible now and then try to reflect it from a Mirror Object.
Front View cannot even understand why the volumetric lights suddenly turned so red and overshadowed the blue color of the Sky
Mirrored View mirrored image degraded while Volumetric Lights are still invisible
p.s. they were all rendered using Bidir
- Attachments
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- Glass Ray Tracing 3 SDS.blend
- (1.33 MiB) Downloaded 110 times