Bump not rendered correctly behind transparency using Branched Path Tracing #41709

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step-ani-motion · 2014-09-04T10:41:41+02:00

step-ani-motion commented

2014-09-04 10:41:41 +02:00

System Information
Win7, Quadro 4000 + Geforce GTX 690

Blender Version
Broken: 2.71 5c1e958

Short description of error
Using Branched Path Tracing.
Happens when rendering an object with strong and narrow bump behind a transparent one.

Exact steps for others to reproduce the error
Open BumpAndTransparent.blend and hit render.
Switch between Branched Path Tracing and Path Tracing Integrator to see the difference.

or

Create two mesh objects. One with a transparent Material and one with diffuse.
Give the diffuse shader a bump or displacement with a very narrow and stretched noise texture.
Place the transparent object in front of the opaque object.
Create an area lamp and point it to the mesh objects in an way that the transparent mesh object ist between light and opaque mesh object .
Set Integrator to Branched Path Tracing.
Hit render
Switch between Branched Path Tracing and Path Tracing Integrator to see the difference.

**System Information** Win7, Quadro 4000 + Geforce GTX 690 **Blender Version** Broken: 2.71 5c1e958 **Short description of error** Using Branched Path Tracing. Happens when rendering an object with strong and narrow bump behind a transparent one. **Exact steps for others to reproduce the error** Open [BumpAndTransparent.blend](https://archive.blender.org/developer/F108684/BumpAndTransparent.blend) and hit render. Switch between Branched Path Tracing and Path Tracing Integrator to see the difference. or 1. Create two mesh objects. One with a transparent Material and one with diffuse. 2. Give the diffuse shader a bump or displacement with a very narrow and stretched noise texture. 3. Place the transparent object in front of the opaque object. 4. Create an area lamp and point it to the mesh objects in an way that the transparent mesh object ist between light and opaque mesh object . 5. Set Integrator to Branched Path Tracing. 6. Hit render 7. Switch between Branched Path Tracing and Path Tracing Integrator to see the difference.

step-ani-motion commented

2014-09-04 10:41:41 +02:00

Changed status to: 'Open'

step-ani-motion commented

2014-09-04 10:41:41 +02:00

Added subscriber: @STEP-ANI-MOTION

Sergey Sharybin self-assigned this 2014-09-04 13:58:09 +02:00

Sergey Sharybin commented

2014-09-04 15:51:21 +02:00

Quick note, this is because ray's derivatives are not being properly updated on the bounce. Not really sure why it's always considered to be a transparent label in the bounce currently, it doesn't give totally correct result by the looks of it and also not sure why kernel_path_surface_bounce() can't be used there to deal with all this stuff.

having a closer look, stay tuned!

Quick note, this is because ray's derivatives are not being properly updated on the bounce. Not really sure why it's always considered to be a transparent label in the bounce currently, it doesn't give totally correct result by the looks of it and also not sure why `kernel_path_surface_bounce()` can't be used there to deal with all this stuff. having a closer look, stay tuned!

blender-admin commented

2014-09-06 14:16:38 +02:00

This issue was referenced by f670a8aeaa

This issue was referenced by f670a8aeaa9ac63f3245bed1ba9bd84c0b575aa3

Sergey Sharybin commented

2014-09-06 14:20:11 +02:00

Changed status from 'Open' to: 'Resolved'

Sergey Sharybin closed this issue

2014-09-06 14:20:11 +02:00

Sergey Sharybin commented

2014-09-06 14:20:11 +02:00

Closed by commit f670a8aeaa.