Compositing not working with loaded images in the render window #82111

New Issue

Sebastien Larocque · 2020-10-26T19:44:01+01:00

2020-10-26 19:44:01 +01:00

System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 452.06

Blender Version
Broken: version: 2.91.0 Beta, branch: master, commit date: 2020-10-23 17:33, hash: 70cc0d7121

Short description of error
Compositing not working with loaded images in the render window

Exact steps for others to reproduce the error

Open the “RenderLoadImageCompositing.blend” attached here.
Go to the render window (menu Render | View Render).
In the render window, menu Image | Open.
Choose the “ImageTest01.exr” attached here.

After these steps, the image is loaded. You should see the white cube. If you do a slight modification in the “Compositing” tab to trigger the compositing engine, nothing happens. Yet, it works correctly when launching the rendering.

Even launching the rendering before loading the image does not help.

The image type loaded does not seem to have an influence on the nature of the problem.

NOTE 1: I read the documentation about the “Load” menu from the render window (https://docs.blender.org/manual/en/latest/editors/image/introduction.html) to get more information. It just says “Load image from a file.”, which is true, but in the context, does not provide a purpose to this functionality. So far, based on what I know from Blender and the problem I encountered, loading an image in the render window has no purpose. In the first place, it looked like something to be able to load our render images and be able to composite. Assuming this is true, this case here is a bug.

NOTE 2: I discovered this bug when trying to continue my compositing work. There are many renderings that take between 12 and 24 hours. Since I cannot render the scene again every time I want to try a new compositing configuration, I need to be able to load the rendered image. That is especially true with different compositing configurations that I tried that crashed Blender (probably lack of memory because of too huge images). I also tried to save my rendering to an EXR to save all the needed information associated with the scene and the image, but the image format did not fix anything.

RenderLoadImageCompositing.blend

**System Information** Operating system: Windows-10-10.0.18362-SP0 64 Bits Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 452.06 **Blender Version** Broken: version: 2.91.0 Beta, branch: master, commit date: 2020-10-23 17:33, hash: `70cc0d7121` **Short description of error** Compositing not working with loaded images in the render window **Exact steps for others to reproduce the error** * Open the “RenderLoadImageCompositing.blend” attached here. * Go to the render window (menu Render | View Render). * In the render window, menu Image | Open. * Choose the “ImageTest01.exr” attached here. After these steps, the image is loaded. You should see the white cube. If you do a slight modification in the “Compositing” tab to trigger the compositing engine, nothing happens. Yet, it works correctly when launching the rendering. Even launching the rendering before loading the image does not help. The image type loaded does not seem to have an influence on the nature of the problem. NOTE 1: I read the documentation about the “Load” menu from the render window (https://docs.blender.org/manual/en/latest/editors/image/introduction.html) to get more information. It just says “Load image from a file.”, which is true, but in the context, does not provide a purpose to this functionality. So far, based on what I know from Blender and the problem I encountered, loading an image in the render window has no purpose. In the first place, it looked like something to be able to load our render images and be able to composite. Assuming this is true, this case here is a bug. NOTE 2: I discovered this bug when trying to continue my compositing work. There are many renderings that take between 12 and 24 hours. Since I cannot render the scene again every time I want to try a new compositing configuration, I need to be able to load the rendered image. That is especially true with different compositing configurations that I tried that crashed Blender (probably lack of memory because of too huge images). I also tried to save my rendering to an EXR to save all the needed information associated with the scene and the image, but the image format did not fix anything. [RenderLoadImageCompositing.blend](https://archive.blender.org/developer/F9101768/RenderLoadImageCompositing.blend) ![ImageTest01.exr](https://archive.blender.org/developer/F9101778/ImageTest01.exr)

Sebastien Larocque commented

2020-10-26 19:44:01 +01:00

Added subscriber: @SebBlender

Germano Cavalcante commented

2020-10-27 21:03:50 +01:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2020-10-27 21:03:50 +01:00

I'm not sure if this is really a bug.
You may be having a misunderstanding of how the image editor works.

To work with images in the compositor, you must use the image node:
https://docs.blender.org/manual/en/dev/compositing/types/input/image.html#image-node

I'm not sure if this is really a bug. You may be having a misunderstanding of how the image editor works. To work with images in the compositor, you must use the image node: https://docs.blender.org/manual/en/dev/compositing/types/input/image.html#image-node

Sebastien Larocque commented

2020-10-28 03:55:50 +01:00

Maybe you’re right, it’s not a bug and I might have a misunderstanding of the image editor. I clearly understand how to render and save my renders to a file and how to use a few tools as well. I don’t pretend to understand everything, but I know one thing for sure, when I don’t know something, I rely on the documentation. At the moment, the document says “Open: Load image from a file.”, which is true, but never explains the purpose. It appeared logic to me that “open” was the inverse process of the “Save” (just aside). Therefore, it would bring back the image to the editor to continue the work and the only work possible that I see is the compositing.

I looked at your “Image” node you mentioned. I’ve been able to load the EXR file saved without the compositing effect and use a “Viewer” node to see the result in the Blender Render window and also by using the “Viewer Node” menu at the top. At the moment, I would say that I can continue my work. There’s a solution. However, we need to modify a bit our compositing node structure to branch the Render Layers and Image node and the Viewer node, but so far that doesn’t seem like a big issue.

Before you flag my report as “closed, invalid”, there is still an issue and a question: What does the open image do? At the moment, this is useless for me and I cannot even rely on the documentation learn more. Generally speaking, the documentation is incomplete on many aspects. There are places with a very short description (not useful because too short and obvious) and just mentioning pretty much what the name of the menu says (like in this case) and there are other places that I have seen where there is a TODO mention in the menu. Here’s one example: https://docs.blender.org/manual/en/latest/addons/import_export/scene_fbx.html

I don’t like to criticize, but clearly the documentation is incomplete. Whether it’s a TODO mention or a very, but very basic description. It needs more love. I’m aware that the human resources are limited and I don’t want to complain, but I need to make my point understood. If the “Open” menu had been better described, I don’t think that I would have filled this report.

I recommend two things:

1. Complete the description of the “Open” menu in this case.
1. Create a task or project to ensure that we have a complete documentation. For many of us, the documentation is the official and first place to look at when we have a problem understanding Blender. It should be our first and our most valuable source of information. Sometimes you don’t need long description, but other times you really need to explain a lot more to understand the purpose of the functionality.

Maybe you’re right, it’s not a bug and I might have a misunderstanding of the image editor. I clearly understand how to render and save my renders to a file and how to use a few tools as well. I don’t pretend to understand everything, but I know one thing for sure, when I don’t know something, I rely on the documentation. At the moment, the document says “Open: Load image from a file.”, which is true, but never explains the purpose. It appeared logic to me that “open” was the inverse process of the “Save” (just aside). Therefore, it would bring back the image to the editor to continue the work and the only work possible that I see is the compositing. I looked at your “Image” node you mentioned. I’ve been able to load the EXR file saved without the compositing effect and use a “Viewer” node to see the result in the Blender Render window and also by using the “Viewer Node” menu at the top. At the moment, I would say that I can continue my work. There’s a solution. However, we need to modify a bit our compositing node structure to branch the Render Layers and Image node and the Viewer node, but so far that doesn’t seem like a big issue. Before you flag my report as “closed, invalid”, there is still an issue and a question: What does the open image do? At the moment, this is useless for me and I cannot even rely on the documentation learn more. Generally speaking, the documentation is incomplete on many aspects. There are places with a very short description (not useful because too short and obvious) and just mentioning pretty much what the name of the menu says (like in this case) and there are other places that I have seen where there is a TODO mention in the menu. Here’s one example: https://docs.blender.org/manual/en/latest/addons/import_export/scene_fbx.html I don’t like to criticize, but clearly the documentation is incomplete. Whether it’s a TODO mention or a very, but very basic description. It needs more love. I’m aware that the human resources are limited and I don’t want to complain, but I need to make my point understood. If the “Open” menu had been better described, I don’t think that I would have filled this report. I recommend two things: * 1. Complete the description of the “Open” menu in this case. * 2. Create a task or project to ensure that we have a complete documentation. For many of us, the documentation is the official and first place to look at when we have a problem understanding Blender. It should be our first and our most valuable source of information. Sometimes you don’t need long description, but other times you really need to explain a lot more to understand the purpose of the functionality.

Richard Antalik commented

2020-10-28 11:20:41 +01:00

Added subscriber: @iss

Richard Antalik commented

2020-10-28 11:20:41 +01:00

Changed status from 'Needs Triage' to: 'Archived'

Richard Antalik closed this issue

2020-10-28 11:20:41 +01:00

Richard Antalik self-assigned this 2020-10-28 11:20:41 +01:00

Richard Antalik commented

2020-10-28 11:20:41 +01:00

Blender's UI is relatively unique so I would probably start here: https://docs.blender.org/manual/en/latest/interface/index.html

When you render image, with default settings it is displayed in image editor in new window. See https://docs.blender.org/manual/en/latest/editors/image/introduction.html
So render window is not much different to other windows. You can change editor to different one after rendering, it will just be called "Blender Render"

Compositor functionality is defined in https://docs.blender.org/manual/en/latest/compositing/introduction.html#getting-started
and then linked to individual node descriptions from which one can understand, that compositing works only on rendered image, that is subsequently displayed in image editor.

It is rather lot of reading which has to be complemented with own experience. This has to be learned in any case though.
That means that there isn't much utility in describing, that when you load image in image editor, it can not be used for compositing or countless other use cases.

I am sure though that our documentation is not perfect or even complete though. But in this case I don't think there is much room for improvement.
Speaking about completeness, there are lot of quirks, at least for advanced user that want to use advanced features that are often hard-coded or very counter intuitive. These may not be fit to document extensively and the only source of truth is in source code. Many people experienced these quirks will know about them and can give you advice how to work around them so for technical support questions please try one of our community websites https://www.blender.org/community/

We value feedback to improve our documentation, so if you think there are information missing or are incorrect, please create new report.

Blender's UI is relatively unique so I would probably start here: https://docs.blender.org/manual/en/latest/interface/index.html When you render image, with default settings it is displayed in image editor in new window. See https://docs.blender.org/manual/en/latest/editors/image/introduction.html So render window is not much different to other windows. You can change editor to different one after rendering, it will just be called "Blender Render" Compositor functionality is defined in https://docs.blender.org/manual/en/latest/compositing/introduction.html#getting-started and then linked to individual node descriptions from which one can understand, that compositing works only on rendered image, that is subsequently displayed in image editor. It is rather lot of reading which has to be complemented with own experience. This has to be learned in any case though. That means that there isn't much utility in describing, that when you load image in image editor, it can not be used for compositing or countless other use cases. I am sure though that our documentation is not perfect or even complete though. But in this case I don't think there is much room for improvement. Speaking about completeness, there are lot of quirks, at least for advanced user that want to use advanced features that are often hard-coded or very counter intuitive. These may not be fit to document extensively and the only source of truth is in source code. Many people experienced these quirks will know about them and can give you advice how to work around them so for technical support questions please try one of our community websites https://www.blender.org/community/ We value feedback to improve our documentation, so if you think there are information missing or are incorrect, please create new report.

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Compositing not working with loaded images in the render window #82111