Glass-Shader Issue

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xxtioo
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Joined: Tue Oct 02, 2018 10:47 am

Glass-Shader Issue

Post by xxtioo »

I created a shader ball from a glass material which reflects about 6-7x repetitions of the environment at the marked spots. I initially assumed that I had made some kind of mistake. But even after a thorough investigation I can't find any error. The repetitions only occur with the glass material, with another shader everything is OK.

I ask for help and would also be very happy, if it is not a mistake, if someone explains to me how it comes to this phenomenon.

I have added the blend-file. Because of the file size the HDRi is missing. You can download it from HDRi-Heaven "palermo_sidewalk_4k" Z-Axis -90°
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Glass-Issue-Marked.png
Shader-Ball-Blanco-Glass-Issue.blend
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Dade
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Re: Glass-Shader Issue

Post by Dade »

It is the way it is supposed to work. The reflected image is only related to the angle of the surface with the camera: if you create a scene with 6 square mirrors and all of them have the same angle (or very similar angles) with the camera, they will reflect all the same part of the HDR image.

HDR is placed at an "infinte" distance, so local position doesn't matter, only the angles do.
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xxtioo
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Re: Glass-Shader Issue

Post by xxtioo »

Unfortunately, this explanation does not seem plausible to me. I have set the material to Mirror for test purposes. There, this effect no longer occurred.
How can this be explained?
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Dade
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Re: Glass-Shader Issue

Post by Dade »

xxtioo wrote: Sun Jan 17, 2021 3:18 pm Unfortunately, this explanation does not seem plausible to me. I have set the material to Mirror for test purposes. There, this effect no longer occurred.
How can this be explained?
Do you have some concrete reason to not believe the result is correct ? For instance, if you render the same scene with Cycles, what do you get ?
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xxtioo
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Re: Glass-Shader Issue

Post by xxtioo »

Under Cycles, it looks something like this, but with significantly fewer repetitions.

I just don't understand why you see this multiple times. Maybe I lack intelligence?
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Dade
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Re: Glass-Shader Issue

Post by Dade »

xxtioo wrote: Sun Jan 17, 2021 6:28 pm I just don't understand why you see this multiple times.
It is likely to be internal reflection, if you reduce the number of max. specular bounces (i.e. depth), you should see less and less repetitions (replaced by just black).
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xxtioo
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Re: Glass-Shader Issue

Post by xxtioo »

Thank you for your help.

I guess it is similar like this:
https://en.wikipedia.org/wiki/Infinity_ ... Effect.jpg
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