Pixels and resolution not for multilayer EXR and Render Result #53768

New Issue

Vincent Girès · 2018-01-12T10:48:41+01:00

Vincent Girès commented

2018-01-12 10:48:41 +01:00

System Information
CentOS - GTX 1070

Blender Version
2.79

Short description of error
Pixels and resolution are not available with multilayer EXR or Render Result images.

Exact steps for others to reproduce the error
import bpy
data = bpy.data
image = data.images['Render result or multilayer EXR']
print(image.pixels) # length is 0
print(image.resolution) # return always Vector((0.0, 0.0))

It is working with regular EXR file.

**System Information** CentOS - GTX 1070 **Blender Version** 2.79 **Short description of error** Pixels and resolution are not available with multilayer EXR or Render Result images. **Exact steps for others to reproduce the error** import bpy data = bpy.data image = data.images['Render result or multilayer EXR'] print(image.pixels) # length is 0 print(image.resolution) # return always Vector((0.0, 0.0)) It is working with regular EXR file.

Vincent Girès commented

2018-01-12 10:48:41 +01:00

Added subscriber: @VincentGires

blender-admin commented

2018-01-12 10:48:41 +01:00

#102806 was marked as duplicate of this issue

blender-admin commented

2018-01-12 10:48:41 +01:00

#90694 was marked as duplicate of this issue

blender-admin commented

2018-01-12 10:48:41 +01:00

#90460 was marked as duplicate of this issue

Philipp Oeser commented

2018-01-12 16:27:04 +01:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2018-01-12 16:27:04 +01:00

true. dont know if you know this already, but a workaround for now could be this
can have a look (, but not sure how involved this task will end up being...)

true. dont know if you know this already, but a workaround for now could be [this ](https://blender.stackexchange.com/questions/2170/how-to-access-render-result-pixels-from-python-script#23309) can have a look (, but not sure how involved this task will end up being...)

Philipp Oeser self-assigned this 2018-01-18 17:55:05 +01:00

Brecht Van Lommel commented

2018-01-26 08:24:37 +01:00

Added subscriber: @brecht

Brecht Van Lommel commented

2018-01-26 08:24:37 +01:00

@lichtwerk, since you claimed this task, are you working on a solution?

This is indeed a gap in our Python API that would be good to fix, though not strictly a bug so up to you if you want to close it or fix it.

@lichtwerk, since you claimed this task, are you working on a solution? This is indeed a gap in our Python API that would be good to fix, though not strictly a bug so up to you if you want to close it or fix it.

Philipp Oeser commented

2018-01-26 09:04:46 +01:00

@brecht: yep, I'm behind schedule here, but I will have a look later today

Philipp Oeser commented

2018-01-29 20:52:42 +01:00

OK, had a first look, but there are remaining questions that I have to wrap my head around.

Getting pixels or size would require aquiring an ImBuf, however the way it is normally done involves an ImageUser (that in turn would have information regarding the corresponding scene, layer, pass, renderslot).
We dont have that from python and I am unsure on what to use as default here. (which scenes renderlayer? which pass, slot?)

And I am still looking at how this "Render Result" is stored in the main database "images". e.g. different scenes RenderResults can have different sizes, however other properties (e.g. display_aspect) are shared across scenes renderResults as it seems...

Long story short: needs a bit more time -- I know, I'm slow... :)

OK, had a first look, but there are remaining questions that I have to wrap my head around. Getting pixels or size would require aquiring an ImBuf, however the way it is normally done involves an ImageUser (that in turn would have information regarding the corresponding scene, layer, pass, renderslot). We dont have that from python and I am unsure on what to use as default here. (which scenes renderlayer? which pass, slot?) And I am still looking at how this "Render Result" is stored in the main database "images". e.g. different scenes RenderResults can have different sizes, however other properties (e.g. display_aspect) are shared across scenes renderResults as it seems... Long story short: needs a bit more time -- I know, I'm slow... :)

Philipp Oeser removed their assignment 2018-02-04 22:21:19 +01:00

Philipp Oeser commented

2018-02-04 22:21:19 +01:00

Unfortunately I'll only be able to look at this in April again, so let others take over....

Brecht Van Lommel commented

2018-03-19 22:40:32 +01:00

Changed status from 'Open' to: 'Archived'

Brecht Van Lommel closed this issue

2018-03-19 22:40:32 +01:00

Brecht Van Lommel self-assigned this 2018-03-19 22:40:32 +01:00

Brecht Van Lommel commented

2018-03-19 22:40:32 +01:00

This is really a known to do item and not a bug, so closing, feature requests are handled elsewhere.

Philipp Oeser commented

2018-04-19 13:08:30 +02:00

Changed status from 'Archived' to: 'Open'

Philipp Oeser reopened this issue

2018-04-19 13:08:30 +02:00

Philipp Oeser commented

2018-04-19 13:08:30 +02:00

also added to TODO here: https:*wiki.blender.org/index.php/Dev:Source/Development/Todo/Scripting
Will have look again if time permits

also added to TODO here: [https:*wiki.blender.org/index.php/Dev:Source/Development/Todo/Scripting ](https:*wiki.blender.org/index.php/Dev:Source/Development/Todo/Scripting) Will have look again if time permits

Pedro Reis commented

2019-08-13 11:23:12 +02:00

Added subscriber: @pedroreis.ad

Pedro Reis commented

2019-08-13 11:28:00 +02:00

I'm currently in a bind at work, and this would be tremendously helpful. I need to access Render Result pixels, and the most lightweight way to do so would be to access them directly. Performance is highly critical for the job at hand, and using GPU offscreen techniques proved to be quite inefficient.

I am willing to help out in this particular task, although it would be my first commit to Blender. I'll become more informed on how to properly contribute code to Blender now, and then try to fix this issue. I'll comment again if I'm blocked somewhere!

I'm currently in a bind at work, and this would be tremendously helpful. I need to access Render Result pixels, and the most lightweight way to do so would be to access them directly. Performance is highly critical for the job at hand, and using GPU offscreen techniques proved to be quite inefficient. I am willing to help out in this particular task, although it would be my first commit to Blender. I'll become more informed on how to properly contribute code to Blender now, and then try to fix this issue. I'll comment again if I'm blocked somewhere!

Pedro Reis commented

2019-09-15 23:48:02 +02:00

Managed to do it, but it is a hacky solution, so hacky that I'm just gonna post it here instead of actually going through with a commit.

Basically the fact that the Render Result has no ImageUser makes the ".pixels" query to return empty. To mitigate this I did the following:

https://github.com/dfelinto/blender/pull/48/files

I used an available fork on GitHub to simplify the process. This commit outlines what was done, but it was basically add an ImageUser to the Image struct, and that ImageUser is assigned to in the OpenGL render init phase. In the image_get_render_result, where this function returned null previously, it now uses the new ImageUser assigned to the Image as a way to get render and scene information.

It's really hacky, but it might help other people :)

Managed to do it, but it is a hacky solution, so hacky that I'm just gonna post it here instead of actually going through with a commit. Basically the fact that the Render Result has no ImageUser makes the ".pixels" query to return empty. To mitigate this I did the following: https://github.com/dfelinto/blender/pull/48/files I used an available fork on GitHub to simplify the process. This commit outlines what was done, but it was basically add an ImageUser to the Image struct, and that ImageUser is assigned to in the OpenGL render init phase. In the image_get_render_result, where this function returned null previously, it now uses the new ImageUser assigned to the Image as a way to get render and scene information. It's really hacky, but it might help other people :)

Brecht Van Lommel removed their assignment 2020-01-18 14:24:01 +01:00

Andrey Sokolov commented

2020-03-22 12:31:25 +01:00

Added subscriber: @Andrey_Sokolov

Andrey Sokolov commented

2020-03-22 12:31:25 +01:00

Is there still no direct way to get pixel data from Render Result and Open EXR Multilayer images through Python API in Blender? It would be extremely useful because reconnecting Viewer to get pixels from each pass in RGBA, convert them to their original passes' types (e.g. Value, Vector, etc.), store in individual images and use pixels from them is pretty time and memory consuming way, especially with animation and dozens of Render Layers with many different passes in the project.

Brecht Van Lommel commented

2021-08-18 16:00:44 +02:00

Added subscribers: @3di, @PratikPB2123

Philipp Oeser commented

2022-10-06 15:32:47 +02:00

Added subscriber: @derekbarker

Philipp Oeser commented

2022-10-06 15:32:47 +02:00

@pedroreis.ad : your hack would only work for OGLRender afaict.
But if we want to solve this for all Render Results, we would need to make getter functions in RNA_api_image that allow to pass in an ImageUser (this could either be taken from e.g. an Editor like the Image Editor -- or ideally even be created from scratch in python). Something along the lines of https:*docs.blender.org/api/3.4/bpy.types.Image.html#bpy.types.Image.filepath_from_user.
I mean, there would need to be a way to tell which layer/pass we actually want to read from, right?

@brecht : would this be the right approach?

@pedroreis.ad : your hack would only work for `OGLRender` afaict. But if we want to solve this for all Render Results, we would need to make getter functions in `RNA_api_image` that allow to pass in an [ImageUser ](https:*docs.blender.org/api/3.4/bpy.types.ImageUser.html) (this could either be taken from e.g. an Editor like the Image Editor -- or ideally even be created from scratch in python). Something along the lines of https:*docs.blender.org/api/3.4/bpy.types.Image.html#bpy.types.Image.filepath_from_user. I mean, there would need to be a way to tell which layer/pass we actually want to read from, right? @brecht : would this be the right approach?

Brecht Van Lommel commented

2022-10-06 16:31:20 +02:00

The right approach is not obvious. Ideally there will be a new data structure that gives full access to views, layers, passes. With ability to iterate over them, read and write pixels, etc. This needs a whole design.

I would rather not have some quick hack.

The right approach is not obvious. Ideally there will be a new data structure that gives full access to views, layers, passes. With ability to iterate over them, read and write pixels, etc. This needs a whole design. I would rather not have some quick hack.

Tiago Petená commented

2022-10-14 18:57:49 +02:00

Added subscriber: @tpet

michael campbell commented

2022-11-27 14:13:35 +01:00

Can we get access to multilayer EXR from python while the new render result data access design is not even a glint in anyone's eye? Perhaps python bindings for the OpenEXR module already in use by Blender?

Lord Odin commented

2022-11-27 14:19:55 +01:00

Yeah, not being able to access pixels is adding multiple seconds to what should be a sub 100ms workflow, and its littering our workspace with files we do not need that we just have to call extra functions to delete in the end. writing to disk to access rendered pixels is a little absurd. Prime example of adding disk to the equation being really dumb is the new tile system in cycles that often renders 2-3x slower than no tiles.

michael campbell commented

2022-11-27 14:36:54 +01:00

Plus there's no way to write the multilayer EXR data back out that I can see. I basically need to edit some of the layers on a multilayer EXR, then overwrite the original with the updated layers. The only way I can think of is to:

load a multilayer EXR into a new image block
load it into a image node in the compositor
connect each of it's sockets to a file output node set to exr (not multilayer)
write it out with render.render()
load in each of the EXR's individually
modify the images
refresh the compositor
create another file output node, this time multilayer
wire all the individual images to it
do another render.render() to save all the images back as layers

It's a nightmare.

Plus there's no way to write the multilayer EXR data back out that I can see. I basically need to edit some of the layers on a multilayer EXR, then overwrite the original with the updated layers. The only way I can think of is to: - load a multilayer EXR into a new image block - load it into a image node in the compositor - connect each of it's sockets to a file output node set to exr (not multilayer) - write it out with render.render() - load in each of the EXR's individually - modify the images - refresh the compositor - create another file output node, this time multilayer - wire all the individual images to it - do another render.render() to save all the images back as layers It's a nightmare.

michael campbell commented

2022-11-28 18:35:03 +01:00

Added subscriber: @EAW

michael campbell commented

2022-11-28 18:35:03 +01:00

Out of interest, should the EXR issue and the Render result data be two seperate issues? It appears that the render data not being accessible is a feature request, but the EXR issue a bug (because image datablock pixel access works for all other file types). @EAW @lichtwerk ? Might be that the image datablock EXR bug is not being addressed whilst unnecessarily waiting for a redesign of the render result data structure? I'm guessing the image datablock already has the necessary structure that enables the compositor to access the layers and views.

michael campbell commented

2022-12-04 10:53:09 +01:00

I just spoke with gpt3 chatbot, and he's in agreement that the blender api should allow access to the multilayer EXR pixels as numpy array :D

and when I asked last night:

import bpy



# Open the EXR file using bpy.data.images.load()

exr_image = bpy.data.images.load("my_exr_image.exr")



# Loop over the layers in the EXR file

for layer in exr_image.layers:

    # Print the layer name and type

    print(layer.name, layer.layer_type)



    # Get the layer data as a NumPy array

    layer_data = layer.get_pixels()

I just spoke with gpt3 chatbot, and he's in agreement that the blender api should allow access to the multilayer EXR pixels as numpy array :D ![image.png](https://archive.blender.org/developer/F13991283/image.png) and when I asked last night: ``` import bpy # Open the EXR file using bpy.data.images.load() exr_image = bpy.data.images.load("my_exr_image.exr") # Loop over the layers in the EXR file for layer in exr_image.layers: # Print the layer name and type print(layer.name, layer.layer_type) # Get the layer data as a NumPy array layer_data = layer.get_pixels() ```

michael campbell commented

2022-12-04 10:56:01 +01:00

Ton Roosendal suggested he agreed it would be a good for this to be a feature of the blender python api. He recommended to make some noise on right click select if we want this in Blender, so upvote it here:

https://blender.community/c/rightclickselect/27zP/

https://blender.community/c/rightclickselect/A1n7/

Ton Roosendal suggested he agreed it would be a good for this to be a feature of the blender python api. He recommended to make some noise on right click select if we want this in Blender, so upvote it here: https://blender.community/c/rightclickselect/27zP/ https://blender.community/c/rightclickselect/A1n7/

Cristóvão Sousa commented

2022-12-23 02:02:26 +01:00

Added subscriber: @cdsousa

Brecht Van Lommel added this to the Render & Cycles project 2023-02-07 19:07:34 +01:00

Philipp Oeser removed the

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Pixels and resolution not for multilayer EXR and Render Result #53768