Import USD materials that are not assigned to any object #97195

New Issue

Zhen Dai · 2022-04-09T12:16:03+02:00

Zhen Dai commented

2022-04-09 12:16:03 +02:00

System Information
Operating system: macOS-12.3-x86_64-i386-64bit 64 Bits
Graphics card: AMD Radeon Pro 580 OpenGL Engine ATI Technologies Inc. 4.1 ATI-4.8.13

Blender Version
Broken: version: 3.1.2, branch: master, commit date: 2022-03-31 17:40, hash: cc66d1020c
Worked: N/A

Short description of error

Failed to import a simple .usda and .usdc file with only 1 default prim defined (and it is a material).

Exact steps for others to reproduce the error

Download a zip file from ambientCG, such as this one: https://ambientcg.com/view?id=PavingStones114 (use 1k-JPG)
Unzip it
Open Blender and Import the unzipped .usda/.usdc file. (try with "Import USD Preview" on and off)
Observe nothing happen, no new material created, no texture imported (it only added a cache file)

However, it is possible to use a third party importer such as: https://github.com/robmcrosby/BlenderUSDZ

Install add-on above
Renamed the zip file from above steps to .usdz
Import it with the add-on
The material appears correctly
Go to shader editor and reset the UV name and it will render correctly (it was named "st" per the usd file)

I do not see why Blender cannot handle the .usda file natively.

**System Information** Operating system: macOS-12.3-x86_64-i386-64bit 64 Bits Graphics card: AMD Radeon Pro 580 OpenGL Engine ATI Technologies Inc. 4.1 ATI-4.8.13 **Blender Version** Broken: version: 3.1.2, branch: master, commit date: 2022-03-31 17:40, hash: `cc66d1020c` Worked: N/A **Short description of error** Failed to import a simple .usda and .usdc file with only 1 default prim defined (and it is a material). **Exact steps for others to reproduce the error** - Download a zip file from ambientCG, such as this one: https://ambientcg.com/view?id=PavingStones114 (use 1k-JPG) - Unzip it - Open Blender and Import the unzipped .usda/.usdc file. (try with "Import USD Preview" on and off) - Observe nothing happen, no new material created, no texture imported (it only added a cache file) However, it is possible to use a third party importer such as: https://github.com/robmcrosby/BlenderUSDZ - Install add-on above - Renamed the zip file from above steps to .usdz - Import it with the add-on - The material appears correctly - Go to shader editor and reset the UV name and it will render correctly (it was named "st" per the usd file) I do not see why Blender cannot handle the .usda file natively.

Zhen Dai commented

2022-04-09 12:16:03 +02:00

Added subscriber: @Zhen-Dai

Zhen Dai commented

2022-04-10 11:20:01 +02:00

Blender was able to import material if the usda contains a dummy mesh, such as this one: https://ambientcg.com/view?id=PavingStones115A

def Mesh "ambientCG_Dummy_Delete_Me"
{
    int[] faceVertexCounts = []
    int[] faceVertexIndices = []
    rel material:binding = </ambientCG_Material_PavingStones115A_1K_JPG>
    point3f[] points = []
    texCoord2f[] primvars:st = []
}

But it also set st as uv map incorrectly on the material.

(Since there is no vertices in the mesh, the uv map is also empty, setting st will never work anyway, not sure how this should be handled.)

(In the meantime, BlenderUSDZ add-on will hang on this file if imported usdz, so fun time for everyone facing this.)

Blender was able to import material if the usda contains a dummy mesh, such as this one: https://ambientcg.com/view?id=PavingStones115A ``` def Mesh "ambientCG_Dummy_Delete_Me" { int[] faceVertexCounts = [] int[] faceVertexIndices = [] rel material:binding = </ambientCG_Material_PavingStones115A_1K_JPG> point3f[] points = [] texCoord2f[] primvars:st = [] } ``` But it also set `st` as uv map incorrectly on the material. (Since there is no vertices in the mesh, the uv map is also empty, setting `st` will never work anyway, not sure how this should be handled.) (In the meantime, BlenderUSDZ add-on will hang on this file if imported usdz, so fun time for everyone facing this.)

Zhen Dai commented

2022-04-10 12:13:34 +02:00

Additional point (but not strictly a bugfix): Blender usd importer could have supported displacement and occlusion map, but it didn't for reasons?

https://graphics.pixar.com/usd/release/spec_usdpreviewsurface.html#preview-surface

Additional point (but not strictly a bugfix): Blender usd importer could have supported `displacement` and `occlusion` map, but it didn't for reasons? https://graphics.pixar.com/usd/release/spec_usdpreviewsurface.html#preview-surface

Philipp Oeser commented

2022-04-11 18:40:15 +02:00

Added subscribers: @makowalski, @lichtwerk

Philipp Oeser commented

2022-04-11 18:40:15 +02:00

Changed status from 'Needs Triage' to: 'Needs Developer To Reproduce'

Philipp Oeser commented

2022-04-11 18:40:15 +02:00

This bugtracker will only handle the native importer, so please no reports about third party Addons.

Can confirm the behavior, no materials are created without dummy objects.
(This is a bit in line with other format importers though, not sure if there is any that just imports materials)

So this might be more like a feature request (a good one though), so maybe @makowalski has this on the TODO already? Or wants to keep this as TODO?

This bugtracker will only handle the native importer, so please no reports about third party Addons. Can confirm the behavior, no materials are created without dummy objects. (This is a bit in line with other format importers though, not sure if there is any that **just** imports materials) So this might be more like a feature request (a good one though), so maybe @makowalski has this on the TODO already? Or wants to keep this as TODO?

Philipp Oeser changed title from ~~Blender 3.1 does not import USD material~~ to Blender 3.1 does not import USD material (without a dummy object)

2022-04-11 18:40:32 +02:00

Michael Kowalski commented

2022-04-12 03:47:54 +02:00

Thanks for reporting this, @zhendai. I agree that this is a good feature request and will investigate. We can probably add an option to import unassigned materials, or something similar.

I'm also investigating importing displacement and occlusion, which can be addressed as a separate task.

Thanks for reporting this, @zhendai. I agree that this is a good feature request and will investigate. We can probably add an option to import unassigned materials, or something similar. I'm also investigating importing `displacement` and `occlusion`, which can be addressed as a separate task.

Michael Kowalski self-assigned this 2022-04-12 03:48:38 +02:00

Zhen Dai commented

2022-04-12 07:17:08 +02:00

In #97195#1339447, @makowalski wrote:
Thanks for reporting this, @zhendai. I agree that this is a good feature request and will investigate. We can probably add an option to import unassigned materials, or something similar.

I'm also investigating importing displacement and occlusion, which can be addressed as a separate task.

Thx, recently Node Wrangler add-on added similar support as well:

https://developer.blender.org/D14134

> In #97195#1339447, @makowalski wrote: > Thanks for reporting this, @zhendai. I agree that this is a good feature request and will investigate. We can probably add an option to import unassigned materials, or something similar. > > I'm also investigating importing `displacement` and `occlusion`, which can be addressed as a separate task. Thx, recently Node Wrangler add-on added similar support as well: https://developer.blender.org/D14134

Bastien Montagne changed title from ~~Blender 3.1 does not import USD material (without a dummy object)~~ to Import USD materials that are not assigned to any object

2022-04-13 17:49:38 +02:00

Kevin Collins commented

2022-05-16 19:13:40 +02:00

Added subscriber: @codeloadgame

Lennart Demes commented

2022-05-21 22:26:07 +02:00

Added subscriber: @Lennart-Demes

Lennart Demes commented

2022-05-21 22:26:07 +02:00

As the creator of ambientCG I would like to say Thanks! When I initially generated all the 1500+ USD files for the website Blender's USDPreviewSurface support was still very limited in general, so I assumed the feature would follow at some point. It's great to see this issue acknowledged.

To help with testing I have prepared some sample files with and without a dummy object on Google Drive .
I just tested these files in the latest 3.3.0-alpha(blender-3.3.0-alpha+master.dfb8c90324c0-windows.amd64-release) and can confirm that only the version with the dummy object gets the material imported, even when disabling the "visible objects only" checkbox while importing.

There is also a DevTalk thread about this, in case someone wants to discuss this situation and possible solutions there instead.

As the creator of ambientCG I would like to say Thanks! When I initially generated all the 1500+ USD files for the website Blender's USDPreviewSurface support was still very limited in general, so I assumed the feature would follow at some point. It's great to see this issue acknowledged. To help with testing I have prepared some sample files with and without a dummy object on [Google Drive ](https://drive.google.com/drive/folders/1QPWUCsE7DTLsGeTZvEr5D6CvlOLiTkFA?usp=sharing). I just tested these files in the latest 3.3.0-alpha(blender-3.3.0-alpha+master.dfb8c90324c0-windows.amd64-release) and can confirm that only the version with the dummy object gets the material imported, even when disabling the "visible objects only" checkbox while importing. There is also a [DevTalk thread ](https://devtalk.blender.org/t/importing-a-material-from-a-usda-file-without-importing-any-geometry/23320) about this, in case someone wants to discuss this situation and possible solutions there instead.

Michael Kowalski commented

2022-05-23 04:36:25 +02:00

Thank you so much for the feedback, @struffel. Indeed, importing unassigned materials is a desirable feature, as I noted above, and I'm about to start work on this. Your files will serve as a good test case, so thank you for providing them!

Lennart Demes commented

2022-08-08 13:28:44 +02:00

Hi, it's been a while. Has there been any recent activity regarding this topic, maybe in one of the daily/bleeding edge builds?

Michael Kowalski commented

2022-08-08 16:39:51 +02:00

In #97195#1401492, @Lennart-Demes wrote:
Hi, it's been a while. Has there been any recent activity regarding this topic, maybe in one of the daily/bleeding edge builds?

Hi @Lennart-Demes This task was partly blocked by unrelated refactoring of the USD material import code, which is now done. I'll be working on the "unassigned materials" import topic next.

> In #97195#1401492, @Lennart-Demes wrote: > Hi, it's been a while. Has there been any recent activity regarding this topic, maybe in one of the daily/bleeding edge builds? Hi @Lennart-Demes This task was partly blocked by unrelated refactoring of the USD material import code, which is now done. I'll be working on the "unassigned materials" import topic next.

Michael Kowalski commented

2022-10-06 15:49:08 +02:00

@Zhen-Dai @Lennart-Demes I've implemented this feature and it's available for you to test in the tmp_usd_import_unbound_mtls experimental build available from the experimental builds downloads page:

https://builder.blender.org/download/experimental/

There is a new Unbound Materials toggle to enable importing unassigned materials, which is off by default. You will probably need to rename the mesh UV set to match what's expected by the material, usually st.

I will create an official patch for this later today. Please let me know if you have feedback or encounter issues.

@Zhen-Dai @Lennart-Demes I've implemented this feature and it's available for you to test in the `tmp_usd_import_unbound_mtls` experimental build available from the experimental builds downloads page: https://builder.blender.org/download/experimental/ There is a new `Unbound Materials` toggle to enable importing unassigned materials, which is off by default. You will probably need to rename the mesh UV set to match what's expected by the material, usually `st`. I will create an official patch for this later today. Please let me know if you have feedback or encounter issues. ![image.png](https://archive.blender.org/developer/F13623230/image.png)

Zhen Dai commented

2022-10-06 17:14:32 +02:00

Thx Michael! Downloading now, I will test it out this Friday.

Lennart Demes commented

2022-10-07 22:25:08 +02:00

Super exciting! I'll test it out tomorrow!

Lennart Demes commented

2022-10-08 10:44:45 +02:00

Okay, looks good to me! All the materials are getting imported.

The thing with the UV map name is a bit annoying of course but I don't see a way of dealing with that without creating issues elsewhere (I could rename my UV maps to Blender's 'UVMap' default name instead of 'st' but that would break stuff for other people).

Okay, looks good to me! All the materials are getting imported. The thing with the UV map name is a bit annoying of course but I don't see a way of dealing with that without creating issues elsewhere (I could rename my UV maps to Blender's 'UVMap' default name instead of 'st' but that would break stuff for other people).

Michael Kowalski commented

2022-10-09 21:34:56 +02:00

In #97195#1429474, @Lennart-Demes wrote:
Okay, looks good to me! All the materials are getting imported.

The thing with the UV map name is a bit annoying of course but I don't see a way of dealing with that without creating issues elsewhere (I could rename my UV maps to Blender's 'UVMap' default name instead of 'st' but that would break stuff for other people).

Thanks so much for testing, @Lennart-Demes!

As for the UV map name issue, we could add an option to automatically rename the maps on import into Blender. E.g., a checkbox to rename st to UVMap, or more generally, some sort of UI to specify how USD primvars should be renamed when converting to Blender attributes. But this will require some thought and discussion, so it should probably be handled in a separate patch.

> In #97195#1429474, @Lennart-Demes wrote: > Okay, looks good to me! All the materials are getting imported. > > The thing with the UV map name is a bit annoying of course but I don't see a way of dealing with that without creating issues elsewhere (I could rename my UV maps to Blender's 'UVMap' default name instead of 'st' but that would break stuff for other people). Thanks so much for testing, @Lennart-Demes! As for the UV map name issue, we could add an option to automatically rename the maps on import into Blender. E.g., a checkbox to rename `st` to `UVMap`, or more generally, some sort of UI to specify how USD primvars should be renamed when converting to Blender attributes. But this will require some thought and discussion, so it should probably be handled in a separate patch.

Lennart Demes commented

2022-12-07 17:38:55 +01:00

Hi again, this feature hasn't made the jump into the official 3.4 release, has it? Is it possible to say with which official release the new material import will be shipped?

Michael Kowalski commented

2022-12-09 17:31:15 +01:00

In #97195#1456280, @Lennart-Demes wrote:
Hi again, this feature hasn't made the jump into the official 3.4 release, has it? Is it possible to say with which official release the new material import will be shipped?

Hi Lennart. Sorry for the late reply. I'm still addressing some issues raised in the patch review and I hope to have a revision for this some time next week. Therefore, this feature has not been merged into 3.4, but I believe it will ready for 3.5, barring any unexpected issues in subsequent reviews.

> In #97195#1456280, @Lennart-Demes wrote: > Hi again, this feature hasn't made the jump into the official 3.4 release, has it? Is it possible to say with which official release the new material import will be shipped? Hi Lennart. Sorry for the late reply. I'm still addressing some issues raised in the patch review and I hope to have a revision for this some time next week. Therefore, this feature has not been merged into 3.4, but I believe it will ready for 3.5, barring any unexpected issues in subsequent reviews.

Michael Kowalski commented

2023-01-13 00:13:27 +01:00

Hi @Lennart-Demes and @zhendai. Just FYI, I submitted a revision to the patch based on the reviews. I also created a patch build for this latest version. If you want to try it, please go to

https://builder.blender.org/download/patch/

and look for the D16172 build. Note that the USD import option for this feature is now called Import All Materials.

Hi @Lennart-Demes and @zhendai. Just FYI, I submitted a revision to the patch based on the reviews. I also created a patch build for this latest version. If you want to try it, please go to https://builder.blender.org/download/patch/ and look for the [D16172](https://archive.blender.org/developer/D16172) build. Note that the USD import option for this feature is now called `Import All Materials`.

Lennart Demes commented

2023-01-16 21:52:46 +01:00

Looks good to me! I tried the usda and usdc files of these materials:

ambientCG.com/a/PavingStones036 (base case)
ambientCG.com/a/ManholeCover004 (metalness and opacity)
ambientCG.com/a/Lava005 (emission)

and they all worked as expected.

Looks good to me! I tried the usda and usdc files of these materials: ambientCG.com/a/PavingStones036 (base case) ambientCG.com/a/ManholeCover004 (metalness and opacity) ambientCG.com/a/Lava005 (emission) and they all worked as expected.

Michael Kowalski commented

2023-01-17 01:41:52 +01:00

Thanks for testing, @Lennart-Demes!