Cycles Fresnel nodes - broken gradients on objects with negative scale (final render only, not viewport) #41219

New Issue

Tom Benedett · 2014-07-28T10:45:02+02:00

Tom Benedett commented

2014-07-28 10:45:02 +02:00

System Information
Windows 7 64-bit, GTX-580, AMD FX-4100, 8 GB RAM

Blender Version
Broken: Buildbot 2.71 698a9a2, and buildbot 2.71 b49e6d0
Worked: 2.70a official

Short description of error
On an object with negative scale, a cycles Fresnel or Layer Weight (just Fresnel output, not Facing) produces a sharp divide in final (but not viewport) renders, instead of a smooth gradient, as seen below:

The sphere on the left has x-scale -1; the one on the right is all positively scaled.

Exact steps for others to reproduce the error
Take some smoothly-curving object, scale it by -1 along some axis (or all three, but not just two, that isn't broken;) and apply a material that uses a Fresnel mixing factor (default IOR/mix factor.) There will be a sharp divide where there should not be on the final render, but not in the viewport render,

Alternatively, see here:

Fresnel_and_Layer_Weight_Scale_Problem.blend

Try the two different Fresnel nodes and the Layer Weight, and observe that only Layer Weight works in final renders, but all three work in the viewport.

**System Information** Windows 7 64-bit, GTX-580, AMD FX-4100, 8 GB RAM **Blender Version** Broken: Buildbot 2.71 698a9a2, and buildbot 2.71 b49e6d0 Worked: 2.70a official **Short description of error** On an object with negative scale, a cycles Fresnel or Layer Weight (just Fresnel output, not Facing) produces a sharp divide in final (but not viewport) renders, instead of a smooth gradient, as seen below: ![Fresnel_and_Layer_Weight_Scale_Problem.png](https://archive.blender.org/developer/F99987/Fresnel_and_Layer_Weight_Scale_Problem.png) The sphere on the left has x-scale -1; the one on the right is all positively scaled. **Exact steps for others to reproduce the error** Take some smoothly-curving object, scale it by -1 along some axis (or all three, but not just two, that isn't broken;) and apply a material that uses a Fresnel mixing factor (default IOR/mix factor.) There will be a sharp divide where there should not be on the final render, but not in the viewport render, Alternatively, see here: [Fresnel_and_Layer_Weight_Scale_Problem.blend](https://archive.blender.org/developer/F99986/Fresnel_and_Layer_Weight_Scale_Problem.blend) Try the two different Fresnel nodes and the Layer Weight, and observe that only Layer Weight works in final renders, but all three work in the viewport.

Tom Benedett commented

2014-07-28 10:45:02 +02:00

Changed status to: 'Open'

Tom Benedett commented

2014-07-28 10:45:02 +02:00

Added subscriber: @moak

Sergey Sharybin was assigned by Bastien Montagne

2014-07-28 12:47:12 +02:00

Bastien Montagne commented

2014-07-28 12:47:12 +02:00

Added subscriber: @mont29

Bastien Montagne commented

2014-07-28 12:47:12 +02:00

Can confirm the issue with latest master as well. Sergey, this is your playground now. ;)

Sergey Sharybin commented

2014-08-12 16:21:45 +02:00

Changed status from 'Open' to: 'Resolved'

Sergey Sharybin closed this issue

2014-08-12 16:21:45 +02:00

Sergey Sharybin commented

2014-08-12 16:21:45 +02:00

This issue had actually been fixed already in 9fcaac5 and eb8f85d. Please grab latest build from builder.blender.org and give it a try.

Let me know if the issue still exists for you, but for until then considering this issue is fixed.

This issue had actually been fixed already in 9fcaac5 and eb8f85d. Please grab latest build from builder.blender.org and give it a try. Let me know if the issue still exists for you, but for until then considering this issue is fixed.

Tom Benedett commented

2014-08-13 10:28:59 +02:00

Nope, not fixed; it's still there as of the very latest Win64 buildbot version (7c9b8aa).

I hit F12 in the example file (using the new Blender version) and still get this image:

Nope, not fixed; it's still there as of the very latest Win64 buildbot version (7c9b8aa). I hit F12 in the example file (using the new Blender version) and still get this image: ![Fresnel_and_Layer_Weight_Scale_Problem_still_here.png](https://archive.blender.org/developer/F102799/Fresnel_and_Layer_Weight_Scale_Problem_still_here.png)

Sergey Sharybin commented

2014-08-13 11:06:16 +02:00

Changed status from 'Resolved' to: 'Open'

Sergey Sharybin reopened this issue

2014-08-13 11:06:16 +02:00

Sergey Sharybin commented

2014-08-13 11:06:16 +02:00

Indeed, for some reason it worked from the desktop..