Compositing - Mix Node #95568

New Issue

Rui Martins · 2022-02-07T01:15:21+01:00

Rui Martins commented

2022-02-07 01:15:21 +01:00

System Information
Operating system: Windows-10-10.0.19043-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 960M/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 471.68

Blender Version
Broken: version: 3.0.1, branch: master, commit date: 2022-01-25 17:19, hash: dc2d180181
Worked: (newest version of Blender that worked as expected)

Short description of error
[Please fill out a short description of the error here]
Mix node (Compositing) displays the image correctly (Viewer Node) however whenever if it is connect to a File Output node it only saves the image that is connected to the first socket of the Mix node.

Exact steps for others to reproduce the error
[Please describe the exact steps needed to reproduce the issue]
[Based on the default startup or an attached .blend file (as simple as possible)]
I was on the compositing tab doing some post-processing work. I had an alpha and two different images that I would like to mix. I added a mix node to the node setup and connected each image (Alpha, Image 1, Image 2) to the corresponding inputs. I used the Viewer Node to have an idea on what I was doing. Everything was fine however when I connected a File Output node and rendered the animation again only the image on the first input was being saved into the folder that I selected (the alpha was applied as well). Inside Blender everything was still great and working accordingly.

I tryed to open the same blend file in another computer and the same happened.

**System Information** Operating system: Windows-10-10.0.19043-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 960M/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 471.68 **Blender Version** Broken: version: 3.0.1, branch: master, commit date: 2022-01-25 17:19, hash: `dc2d180181` Worked: (newest version of Blender that worked as expected) **Short description of error** [Please fill out a short description of the error here] Mix node (Compositing) displays the image correctly (Viewer Node) however whenever if it is connect to a File Output node it only saves the image that is connected to the first socket of the Mix node. **Exact steps for others to reproduce the error** [Please describe the exact steps needed to reproduce the issue] [Based on the default startup or an attached .blend file (as simple as possible)] I was on the compositing tab doing some post-processing work. I had an alpha and two different images that I would like to mix. I added a mix node to the node setup and connected each image (Alpha, Image 1, Image 2) to the corresponding inputs. I used the Viewer Node to have an idea on what I was doing. Everything was fine however when I connected a File Output node and rendered the animation again only the image on the first input was being saved into the folder that I selected (the alpha was applied as well). Inside Blender everything was still great and working accordingly. I tryed to open the same blend file in another computer and the same happened.

Rui Martins commented

2022-02-07 01:15:21 +01:00

Added subscriber: @Rui_Martins

Evan Wilson commented

2022-02-07 03:13:53 +01:00

Added subscriber: @EAW

Evan Wilson commented

2022-02-07 03:13:53 +01:00

Changed status from 'Needs Triage' to: 'Needs User Info'

Evan Wilson commented

2022-02-07 03:13:53 +01:00

Please upload an example Blend file.

Pratik Borhade commented

2022-02-07 04:57:50 +01:00

Added subscriber: @PratikPB2123

Rui Martins commented

2022-02-07 18:08:11 +01:00

I will have to upload the file that I was working with since I could not find a way to reproduce the bug on a new empty file.d_bosstv_Day.001.blend

I will have to upload the file that I was working with since I could not find a way to reproduce the bug on a new empty file.[d_bosstv_Day.001.blend](https://archive.blender.org/developer/F12852922/d_bosstv_Day.001.blend)

Evan Wilson commented

2022-02-07 19:55:47 +01:00

Changed status from 'Needs User Info' to: 'Needs Triage'

Germano Cavalcante commented

2022-02-08 15:45:07 +01:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2022-02-08 15:45:07 +01:00

I investigated the huge file (which could be simplified) and I was able to detect the problem.
It's the same problem as #81199 (Some effects [bloom, smoke, fire, ..] still don't save in PNG with transparent background (occlusion vs. emission)).
In the file, the environment works as an emission with alpha 0%.
PNG does not support emission, so anything with alpha 0% is pre-multiplied and discarded.
Try to work with image formats other than PNG.

I investigated the huge file (which could be simplified) and I was able to detect the problem. It's the same problem as #81199 (Some effects [bloom, smoke, fire, ..] still don't save in PNG with transparent background (occlusion vs. emission)). In the file, the environment works as an emission with alpha 0%. PNG does not support emission, so anything with alpha 0% is pre-multiplied and discarded. Try to work with image formats other than PNG.

Germano Cavalcante commented

2022-02-08 15:45:23 +01:00

Closed as duplicate of #81199

Germano Cavalcante closed this issue

2022-02-08 15:45:23 +01:00

Philipp Oeser commented

2022-02-08 15:47:57 +01:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2022-02-08 15:47:57 +01:00

Changed status from 'Duplicate' to: 'Archived'

Philipp Oeser commented

2022-02-08 15:47:57 +01:00

Not sure I understand correctly:

the renderlayer has alpha, this carries on in the nodetree, you can check by enabling Use Alpha on the viewer.
{F12855346 size=full}
why not use the Alpha Over node?
{F12855373 size=full}

There are of course other methods to handle the alpha (e.g. Set Alpha on the renderlayer, ...)

This does not look like a bug to me, will archive.
(but of course feel free to comment again if this is a misunderstanding or if issues persist).

Not sure I understand correctly: - the renderlayer has alpha, this carries on in the nodetree, you can check by enabling `Use Alpha` on the viewer. {[F12855346](https://archive.blender.org/developer/F12855346/image.png) size=full} - why not use the Alpha Over node? {[F12855373](https://archive.blender.org/developer/F12855373/image.png) size=full} There are of course other methods to handle the alpha (e.g. `Set Alpha` on the renderlayer, ...) This does not look like a bug to me, will archive. (but of course feel free to comment again if this is a misunderstanding or if issues persist).

Philipp Oeser commented

2022-02-08 15:55:13 +01:00

In #95568#1304075, @mano-wii wrote:
I investigated the huge file (which could be simplified) and I was able to detect the problem.
It's the same problem as #81199 (Some effects [bloom, smoke, fire, ..] still don't save in PNG with transparent background (occlusion vs. emission)).
In the file, the environment works as an emission with alpha 0%.
PNG does not support emission, so anything with alpha 0% is pre-multiplied and discarded.
Try to work with image formats other than PNG.

Well yep, that on top is also true

> In #95568#1304075, @mano-wii wrote: > I investigated the huge file (which could be simplified) and I was able to detect the problem. > It's the same problem as #81199 (Some effects [bloom, smoke, fire, ..] still don't save in PNG with transparent background (occlusion vs. emission)). > In the file, the environment works as an emission with alpha 0%. > PNG does not support emission, so anything with alpha 0% is pre-multiplied and discarded. > Try to work with image formats other than PNG. Well yep, that on top is also true

Rui Martins commented

2022-02-08 19:56:07 +01:00

Alright. Thank you very much. I will use other methods

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Compositing - Mix Node #95568