[cycles] Lightpath/Transparent depth is acting wonky. #51723

New Issue

Ray molenkamp · 2017-06-06T01:14:44+02:00

Ray molenkamp commented

2017-06-06 01:14:44 +02:00

System Information
Win7/x64

Blender Version
Broken: Latest master
Worked: (optional)

Short description of error

I'm trying to create a material where an object is only visible when it is behind a glass plane, should be easy enough.

However the red monkey turns black instead of transparent, also the green money (similar shader just inverted the inputs of the mix node) has some artifacting

Repo steps:

Open up .blend, hit render

monkey_business.blend

**System Information** Win7/x64 **Blender Version** Broken: Latest master Worked: (optional) **Short description of error** I'm trying to create a material where an object is only visible when it is behind a glass plane, should be easy enough. ![money_business.png](https://archive.blender.org/developer/F621525/money_business.png) However the red monkey turns black instead of transparent, also the green money (similar shader just inverted the inputs of the mix node) has some artifacting Repo steps: Open up .blend, hit render [monkey_business.blend](https://archive.blender.org/developer/F621527/monkey_business.blend)

Ray molenkamp commented

2017-06-06 01:14:44 +02:00

Changed status to: 'Open'

Ray molenkamp commented

2017-06-06 01:14:44 +02:00

Added subscriber: @LazyDodo

Brecht Van Lommel commented

2017-06-06 01:42:01 +02:00

Added subscriber: @brecht

Brecht Van Lommel commented

2017-06-06 01:42:01 +02:00

Changed status from 'Open' to: 'Archived'

Brecht Van Lommel closed this issue

2017-06-06 01:42:01 +02:00

Brecht Van Lommel self-assigned this 2017-06-06 01:42:01 +02:00

Brecht Van Lommel commented

2017-06-06 01:42:01 +02:00

With the red monkey the front side faces will become transparent, and then the back side faces will become diffuse again because they are behind a transparent surface. It's black because there's no light entering the inside of the mesh. Making backfacing geometry transparent as well could solve that problem.

For the green monkey the black happens because the max transparency depth of 8 is reached, increasing it solves that.

So no bug here as far as I can tell.

With the red monkey the front side faces will become transparent, and then the back side faces will become diffuse again because they are behind a transparent surface. It's black because there's no light entering the inside of the mesh. Making backfacing geometry transparent as well could solve that problem. For the green monkey the black happens because the max transparency depth of 8 is reached, increasing it solves that. So no bug here as far as I can tell.

Brecht Van Lommel commented

2017-06-06 01:46:18 +02:00

Using backfacing wouldn't work entirely for the monkey by the way, because it's not a closed mesh.

Ray molenkamp commented

2017-06-06 02:06:33 +02:00

You're absolutely correct ,it works fine when i replace the monkeys with a simple plane! thanks for your insight!

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[cycles] Lightpath/Transparent depth is acting wonky. #51723