principled shader alpha bleeding issues in Eevee #70586

New Issue

MACHIN3 · 2019-10-06T15:21:58+02:00

MACHIN3 commented

2019-10-06 15:21:58 +02:00

System Information
Operating system: Linux-4.13.10-041310-generic-x86_64-with-debian-stretch-sid 64 Bits
Graphics card: GeForce GTX 1050/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 390.67

Blender Version
Broken: version: 2.81 (sub 13), branch: master, commit date: 2019-10-04 22:33, hash: ab519b91b2
Worked: 2.80 stable

Short description of error
This is maybe related to this issue reported in May.

The issue presents itself as what looks like black bleeding in, when using the alpha socket of the principled pbr shader. Curiously, it only happens when either the Subsurface, Clearcoat or Transmission sockets are connected, and even if they feed in a value of 0.
The issue does not seem to be related to the interpolation used of the alpha texture. Neither is there any actual black color present- for instance in a color map - that could be bleeding in from the outside.
The issue is not present in the 2.80 stable release.
It can be avoided by mixing with a transparent shader instead, but I was hoping that would be a thing of the past now.

video demo
principled_shader_alpha_bleeding_issues.zip

Exact steps for others to reproduce the error

open the blend contained in the above zip file in a (recent?) 2.81 build
the Y-facing circle and 'Access Electrical' decal display a dark outline at the alpha border
- mute or disconnect all the 3 value inputs, the bleeding vanishes
- unmute or reconnect any of the 3, and it comes back
the X-facing decals don't have that issue, the transparency is craeted by mixing a transparent shader
load the blend in 2.80, and everything should look fine

**System Information** Operating system: Linux-4.13.10-041310-generic-x86_64-with-debian-stretch-sid 64 Bits Graphics card: GeForce GTX 1050/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 390.67 **Blender Version** Broken: version: 2.81 (sub 13), branch: master, commit date: 2019-10-04 22:33, hash: `ab519b91b2` Worked: 2.80 stable **Short description of error** This is maybe related to [this issue ](https://developer.blender.org/T64883) reported in May. The issue presents itself as what looks like black bleeding in, when using the alpha socket of the principled pbr shader. Curiously, it only happens when either the Subsurface, Clearcoat or Transmission sockets are connected, and even if they feed in a value of 0. The issue does not seem to be related to the interpolation used of the alpha texture. Neither is there any actual black color present- for instance in a color map - that could be bleeding in from the outside. The issue is not present in the 2.80 stable release. It can be avoided by mixing with a transparent shader instead, but I was hoping that would be a thing of the past now. ![alpha_bleeding.png](https://archive.blender.org/developer/F7792740/alpha_bleeding.png) ![no_bleeding_when_mixing_transparent_shader.png](https://archive.blender.org/developer/F7792742/no_bleeding_when_mixing_transparent_shader.png) [video demo ](https://www.youtube.com/watch?v=Ss78eBp3JZQ) [principled_shader_alpha_bleeding_issues.zip](https://archive.blender.org/developer/F7792733/principled_shader_alpha_bleeding_issues.zip) **Exact steps for others to reproduce the error** * open the blend contained in the above zip file in a (recent?) 2.81 build * the Y-facing circle and 'Access Electrical' decal display a dark outline at the alpha border * mute or disconnect all the 3 value inputs, the bleeding vanishes * unmute or reconnect any of the 3, and it comes back * the X-facing decals don't have that issue, the transparency is craeted by mixing a transparent shader * load the blend in 2.80, and everything should look fine

MACHIN3 commented

2019-10-06 15:21:58 +02:00

Added subscriber: @MACHIN3

MACHIN3 commented

2019-10-06 15:27:50 +02:00

I've tested in the oldest 2.81 build I still had - cb7ead2e3b from August 15th - and it's already present there. So it doesn't look like a recent change caused this.

I've tested in the oldest 2.81 build I still had - cb7ead2e3b62 from August 15th - and it's already present there. So it doesn't look like a recent change caused this.

MACHIN3 changed title from ~~principled shader alpha bleeding issues~~ to principled shader alpha bleeding issues in Eevee

2019-10-06 15:30:26 +02:00

Piotr commented

2019-10-07 14:44:40 +02:00

Added subscriber: @Pinnhead

Piotr commented

2019-10-07 14:44:40 +02:00

I have the same issues with Y-facing circle in blender-2.81-54a9649e2636-windows64

marc dion commented

2019-10-07 17:06:22 +02:00

Added subscriber: @MarcClintDion

marc dion commented

2019-10-07 17:06:22 +02:00

Windows 10 Home (Auto Update)
GTX 1070 (Version: 26.21.14.3086)

The issue wasn't present for the July 30th build but is present for the Aug 20 build as shown in the following two images. (The splash screens are included for the date and hash)

Windows 10 Home (Auto Update) GTX 1070 (Version: 26.21.14.3086) The issue wasn't present for the July 30th build but is present for the Aug 20 build as shown in the following two images. (The splash screens are included for the date and hash) ![2019-07-30.png](https://archive.blender.org/developer/F7794743/2019-07-30.png) ![2018-08-20.png](https://archive.blender.org/developer/F7794744/2018-08-20.png)

Clément Foucault self-assigned this 2019-10-08 12:38:57 +02:00

blender-admin commented

2019-10-08 20:29:27 +02:00

This issue was referenced by 576c782b11

This issue was referenced by 576c782b11f629130b1226f37d4fd467f8793247

Clément Foucault commented

2019-10-08 20:30:38 +02:00

Changed status from 'Open' to: 'Resolved'

Clément Foucault closed this issue

2019-10-08 20:30:38 +02:00

MACHIN3 commented

2019-10-09 13:29:19 +02:00

Thanks, it's working great now. As long as the material is using Alpha Blend. In Alpha Hashed the issue returns. Not sure if that is just unavoidable, or if it's an oversight.

alpha_mapping_issues_alpha_blend_vs_hashed.blend

Thanks, it's working great now. As long as the material is using Alpha Blend. In Alpha Hashed the issue returns. Not sure if that is just unavoidable, or if it's an oversight. ![alpha_blend.png](https://archive.blender.org/developer/F7798699/alpha_blend.png) ![alpha_hashed.png](https://archive.blender.org/developer/F7798701/alpha_hashed.png) [alpha_mapping_issues_alpha_blend_vs_hashed.blend](https://archive.blender.org/developer/F7798698/alpha_mapping_issues_alpha_blend_vs_hashed.blend)

Clément Foucault commented

2019-10-09 13:43:16 +02:00

The alpha hashed issue has been reported already #70640. It's slightly different but I know a fix.

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principled shader alpha bleeding issues in Eevee #70586