USD image assets paths are not resolved in a cross platform manner #97362

New Issue

Jamie Cope · 2022-04-15T18:34:45+02:00

Jamie Cope commented

2022-04-15 18:34:45 +02:00

USD files exported with image assets on Windows can't be loaded on Linux and vice versa. The same happens with Windows and MacOS.

Original Report

System Information
Operating system: Windows-10-10.0.19044-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 3080 Laptop GPU/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 466.42

Blender Version
Broken: version: 3.1.2, branch: master, commit date: 2022-03-31 17:40, hash: cc66d1020c
Worked: (newest version of Blender that worked as expected)

Short description of error

USD Exporter is using back slashes for texture paths. When zipped to a usdz, this causes MacOS/Quicklook to fail loading the texture. If forward slashes are used, loading works as expected.

Exact steps for others to reproduce the error

Add a diffuse texture to default cube
Export as usda with textures and relative texture paths
Zip usda and texture folder to usdz (no compression)
Try to preview with Quicklook - no texture
Redo above steps but edit usda to use forward slashes before zipping and preview works as expected with texture.

USD files exported with image assets on Windows can't be loaded on Linux and vice versa. The same happens with Windows and MacOS. **Original Report** **System Information** Operating system: Windows-10-10.0.19044-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 3080 Laptop GPU/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 466.42 **Blender Version** Broken: version: 3.1.2, branch: master, commit date: 2022-03-31 17:40, hash: `cc66d1020c` Worked: (newest version of Blender that worked as expected) **Short description of error** USD Exporter is using back slashes for texture paths. When zipped to a usdz, this causes MacOS/Quicklook to fail loading the texture. If forward slashes are used, loading works as expected. **Exact steps for others to reproduce the error** - Add a diffuse texture to default cube - Export as usda with textures and relative texture paths - Zip usda and texture folder to usdz (no compression) - Try to preview with Quicklook - no texture - Redo above steps but edit usda to use forward slashes before zipping and preview works as expected with texture.

Jamie Cope commented

2022-04-15 18:34:45 +02:00

Added subscriber: @copeg

Pratik Borhade commented

2022-04-16 11:50:38 +02:00

Added subscriber: @PratikPB2123

Omar Emara commented

2022-05-24 16:11:54 +02:00

Added subscriber: @OmarEmaraDev

Omar Emara commented

2022-05-24 16:11:54 +02:00

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

Omar Emara commented

2022-05-24 16:11:54 +02:00

Can you attach a small sample file with back slashes for us to debug this better?

Jamie Cope commented

2022-05-24 16:25:19 +02:00

usd_test.zip

Sure, here is the default cube with a texture exported as .usda along with the textures folder and texture.

[usd_test.zip](https://archive.blender.org/developer/F13102973/usd_test.zip) Sure, here is the default cube with a texture exported as .usda along with the textures folder and texture.

Omar Emara commented

2022-05-25 08:38:33 +02:00

So apparently I can't import that file back into Blender on Linux or Mac due to the Windows-like paths. So that's different already a problem.

WARNING: Couldn't resolve image asset '@.\textures\scene-image-medium.jpg@' for Texture Image node.

The question is, can UNIX-like paths import into Blender on Windows?
Can you try that? Does the edited usda with forward slashes import back into Blender on Windows for you?

                asset inputs:file = @./textures/scene-image-medium.jpg@

So apparently I can't import that file back into Blender on Linux or Mac due to the Windows-like paths. So that's different already a problem. ``` WARNING: Couldn't resolve image asset '@.\textures\scene-image-medium.jpg@' for Texture Image node. ``` The question is, can UNIX-like paths import into Blender on Windows? Can you try that? Does the edited usda with forward slashes import back into Blender on Windows for you? ``` asset inputs:file = @./textures/scene-image-medium.jpg@ ```

Jamie Cope commented

2022-05-25 15:44:59 +02:00

I'm not getting any errors importing that file with either forward or backslashes on Windows, but either way it also doesn't seem to import the texture.

Omar Emara commented

2022-05-25 16:26:02 +02:00

Just to double check, did you enable Import USD Preview when importing? Because otherwise textures will not be imported I think.
Also, is there any error in the console after importing?

Just to double check, did you enable Import USD Preview when importing? Because otherwise textures will not be imported I think. Also, is there any error in the console after importing?

Jamie Cope commented

2022-05-25 16:32:41 +02:00

Yes, I enabled Import USD Preview in both cases, but other than that just the default options.

I don't see any errors, but get 4 instances of this warning after import:

Warning (secondary thread): in GetType at line 385 of E:\db19\build\S\VS1564R\build\usd\src\external_usd\pxr\base\vt\value.cpp -- Returning unknown type for VtValue with unregistered C++ type pxr_half::half

Yes, I enabled Import USD Preview in both cases, but other than that just the default options. I don't see any errors, but get 4 instances of this warning after import: Warning (secondary thread): in GetType at line 385 of E:\db19\build\S\VS1564R\build\usd\src\external_usd\pxr\base\vt\value.cpp -- Returning unknown type for VtValue with unregistered C++ type pxr_half::half

Omar Emara commented

2022-05-26 09:16:07 +02:00

Here is what I found so far. USD assets can have any path format, including Windows or UNIX paths, however, the importing application will have to support resolving that format, from the documentation:

In general, Ar does not impose any requirements or restrictions on the format of an asset path or resolved path. Users are free to use whatever path syntax they want as long as they are supported by their underlying resolver implementations.

There is a default resolver in USD, which I guess is used by Blender by default, in that resolver, we see:

    // Ensure we are using forward slashes and not back slashes.
    std::string forwardPath = anchorPath;
    std::replace(forwardPath.begin(), forwardPath.end(), '\\', '/');

Moreover, on Windows TfNormPath is called to also replace backward slashes with forward slashes and lower case drive specifiers. So the default resolver will eventually produce a UNIX path which Blender can accept.

So I suspect Quicklook is at fault here, maybe it uses a custom resolver that doesn't do this normalization? Have you tried contacting their support about this?

For the other issue, that is, textures are not importing at all no matter how the paths are constructed, can you open a separate report for it?

Here is what I found so far. USD assets can have any path format, including Windows or UNIX paths, however, the importing application will have to support resolving that format, from the [documentation](https://graphics.pixar.com/usd/release/api/ar_page_front.html#ar_paths): > In general, Ar does not impose any requirements or restrictions on the format of an asset path or resolved path. Users are free to use whatever path syntax they want as long as they are supported by their underlying resolver implementations. There is a default resolver in USD, which I guess is used by Blender by default, in that resolver, [we see](https://github.com/PixarAnimationStudios/USD/blob/release/pxr/usd/ar/defaultResolver_v2.cpp#L78): ``` // Ensure we are using forward slashes and not back slashes. std::string forwardPath = anchorPath; std::replace(forwardPath.begin(), forwardPath.end(), '\\', '/'); ``` Moreover, on Windows `TfNormPath` is called to also replace backward slashes with forward slashes and lower case drive specifiers. So the default resolver will eventually produce a UNIX path which Blender can accept. So I suspect Quicklook is at fault here, maybe it uses a custom resolver that doesn't do this normalization? Have you tried contacting their support about this? --- For the other issue, that is, textures are not importing at all no matter how the paths are constructed, can you open a separate report for it?

Jamie Cope commented

2022-05-27 16:19:23 +02:00

Based on the your quote from the spec, yes it seems like Quicklook should handle those paths. I have not contacted them, but can try. It's odd though because USD files produced with other tools work fine, so they must all be using forward slashes.

That being said, it still seems inconsistent that the importer is ensuring forward slashes when resolving but the exporter is using backslashes (or maybe it's platform dependent?) - the other internal file structure paths look to use forward slashes regardless.

Also, shouldn't that resolver solve your "WARNING: Couldn't resolve image asset '@.\textures\scene-image-medium.jpg@' for Texture Image node." issue?

Based on the your quote from the spec, yes it seems like Quicklook should handle those paths. I have not contacted them, but can try. It's odd though because USD files produced with other tools work fine, so they must all be using forward slashes. That being said, it still seems inconsistent that the importer is ensuring forward slashes when resolving but the exporter is using backslashes (or maybe it's platform dependent?) - the other internal file structure paths look to use forward slashes regardless. Also, shouldn't that resolver solve your "WARNING: Couldn't resolve image asset '@.\textures\scene-image-medium.jpg@' for Texture Image node." issue?

Omar Emara commented

2022-05-27 18:51:10 +02:00

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

Omar Emara commented

2022-05-27 18:51:10 +02:00

The exporter seems to just the path as is, so it is platform dependent, while the importer should do the normalization and resolution.

You are right, we should expect it to resolve correctly in my case, but apparently the path is read as an empty string, so something is wrong somewhere.

The exporter seems to just the path as is, so it is platform dependent, while the importer should do the normalization and resolution. You are right, we should expect it to resolve correctly in my case, but apparently the path is read as an empty string, so something is wrong somewhere.

Omar Emara commented

2022-06-08 09:53:16 +02:00

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

Omar Emara commented

2022-06-08 09:53:16 +02:00

Setting this to confirmed as path resolution doesn't seem to be working in a cross platform manner. I tried to investigate this myself, but a more experience developer should look into this instead.

Omar Emara changed title from ~~USD export texture path formatting causes problems on MacOS~~ to USD image assets paths are not resolved in a cross platform manner

2022-06-08 09:56:32 +02:00

Philipp Oeser commented

2022-06-08 10:22:15 +02:00

Added subscribers: @makowalski, @lichtwerk

Philipp Oeser commented

2022-06-08 10:22:15 +02:00

CC @makowalski

Michael Kowalski commented

2022-06-08 16:31:10 +02:00

Thanks for investigating this, @OmarSquircleArt. I believe the solution is to ensure that relative paths have forward slashes when exporting USD from Blender. I will take this task and will work on a fix in the next couple of days.

The forward slashes should work when importing back on Windows. It didn't work for this example because of the material-name collision issue, being addressed here:

https://developer.blender.org/D14869

Because of this issue, the material wouldn't load, regardless of whether forward or back slashes are used. If I rename Material to Material2 in that USDA, the materials load fine with the forward slashes on Windows.

Thanks for investigating this, @OmarSquircleArt. I believe the solution is to ensure that relative paths have forward slashes when exporting USD from Blender. I will take this task and will work on a fix in the next couple of days. The forward slashes should work when importing back on Windows. It didn't work for this example because of the material-name collision issue, being addressed here: https://developer.blender.org/D14869 Because of this issue, the material wouldn't load, regardless of whether forward or back slashes are used. If I rename `Material` to `Material2` in that USDA, the materials load fine with the forward slashes on Windows.

Michael Kowalski self-assigned this 2022-06-08 16:31:36 +02:00

blender-admin commented

2022-06-10 21:07:45 +02:00

This issue was referenced by add1da52ad

This issue was referenced by add1da52ad783e33e8abb0a790ddc97dd89dab92

Michael Kowalski commented

2022-06-10 21:12:03 +02:00

Changed status from 'Confirmed' to: 'Resolved'

Michael Kowalski closed this issue

2022-06-10 21:12:03 +02:00

Michael Kowalski commented

2022-06-10 21:15:34 +02:00

@copeg Hi Jamie. The fix is committed. Please let me know if there are remaining issues with regard to the texture paths.

Jamie Cope commented

2022-06-10 21:16:31 +02:00

Excellent! Thanks so much Michael.

Bastien Montagne added this to the Pipeline, Assets & IO project 2023-02-09 15:40:49 +01:00

Bastien Montagne removed this from the Pipeline, Assets & IO project 2023-02-10 12:49:29 +01:00

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USD image assets paths are not resolved in a cross platform manner #97362