Mirrored UV have bad tangent space #53750

New Issue

Clément Foucault · 2018-01-10T10:10:57+01:00

Clément Foucault commented

2018-01-10 10:10:57 +01:00

Mirrored UVs produce bad normal map output. This is due to tangent calculation/upload to GPU.

Even more strange is the fact that building without cycles gives a different result.

mirro_normalmap_bug.blend

2.8 With Cycles (only left half is correct (switch to cycles to see correct result)

2.8 Without Cycles (seems completly inverted)

This was with debug build by the way.

Mirrored UVs produce bad normal map output. This is due to tangent calculation/upload to GPU. Even more strange is the fact that building without cycles gives a different result. [mirro_normalmap_bug.blend](https://archive.blender.org/developer/F1777389/mirro_normalmap_bug.blend) ![28_without_asan_with_cycles.png](https://archive.blender.org/developer/F1777394/28_without_asan_with_cycles.png) 2.8 With Cycles (only left half is correct (switch to cycles to see correct result) ![28_with_asan_without_cycles.png](https://archive.blender.org/developer/F1777396/28_with_asan_without_cycles.png) 2.8 Without Cycles (seems completly inverted) This was with debug build by the way.

Campbell Barton was assigned by Clément Foucault

2018-01-10 10:10:57 +01:00

Clément Foucault commented

2018-01-10 10:10:57 +01:00

Added subscriber: @fclem

blender-admin commented

2018-01-10 10:10:57 +01:00

#57692 was marked as duplicate of this issue

blender-admin commented

2018-01-10 10:10:57 +01:00

#57021 was marked as duplicate of this issue

Campbell Barton commented

2018-01-10 12:09:09 +01:00

Changed status from 'Open' to: 'Archived'

Campbell Barton closed this issue

2018-01-10 12:09:09 +01:00

Campbell Barton commented

2018-01-10 12:09:09 +01:00

The mirrored UV's are a copy in this case - not a continuous unwrap, so there are seams.

The difference without cycles is it's using Blender-Internal rendering engine. Which uses flipped tangents.
(double checked and this is the case for 2.79).

So there is no bug here as far as I can see.

The mirrored UV's are a copy in this case - not a continuous unwrap, so there are seams. The difference without cycles is it's using Blender-Internal rendering engine. Which uses flipped tangents. (double checked and this is the case for 2.79). So there is no bug here as far as I can see.

Clément Foucault commented

2018-01-10 12:21:22 +01:00

My bad the description is not good.

I should have stated that the screenshot "2.8 with cycles" is faulty. If you compare it to the cycles rendered results.

The problem is not the seam but the tangent direction.

This is the expected result.

My bad the description is not good. I should have stated that the screenshot "2.8 with cycles" is faulty. If you compare it to the cycles rendered results. The problem is not the seam but the tangent direction. This is the expected result. ![cycle.png](https://archive.blender.org/developer/F1778159/cycle.png)

Clément Foucault commented

2018-01-10 12:21:31 +01:00

Changed status from 'Archived' to: 'Open'

Clément Foucault reopened this issue

2018-01-10 12:21:31 +01:00

msalv commented

2018-05-29 18:34:50 +02:00

Added subscriber: @moisessalvador

Enrique Roberto Huerta Soto commented

2018-09-20 07:55:47 +02:00

Added subscriber: @KillerKick

Bohdan Lvov commented

2018-09-24 20:04:36 +02:00

Added subscriber: @ostapblender

Michal commented

2018-10-15 23:06:29 +02:00

Added subscriber: @Veezen

Michal commented

2018-10-15 23:06:29 +02:00

I have similar problem and I posted this problem on Blenderartists.

In short: every mirrored UV island with baked normal maps doesn't work in Eevee.

https://blenderartists.org/t/normal-map-in-eevee-have-big-problems-mirrored-uv-islands/1130183

I have similar problem and I posted this problem on Blenderartists. In short: every mirrored UV island with baked normal maps doesn't work in Eevee. https://blenderartists.org/t/normal-map-in-eevee-have-big-problems-mirrored-uv-islands/1130183

msalv commented

2018-10-16 15:04:22 +02:00

Consider having this ready for the beta milestone

Enrique Roberto Huerta Soto commented

2018-11-08 07:18:21 +01:00

this is how the mirrored uvs show in eevee

this is how they look in cycles

just wanted to know if there's a way to fix it in eevee

this is how the mirrored uvs show in eevee ![eevee.PNG](https://archive.blender.org/developer/F5436677/eevee.PNG) this is how they look in cycles ![cycles.PNG](https://archive.blender.org/developer/F5436678/cycles.PNG) just wanted to know if there's a way to fix it in eevee

Brecht Van Lommel commented

2018-11-08 11:08:31 +01:00

Added subscriber: @mikhluz