Bug: USD exporter doesn't include hair/curve UVs #120042

New Issue

Brian Hanke · 2024-03-29T01:07:33+01:00

Brian Hanke commented

2024-03-29 01:07:33 +01:00

System Information

Operating system: Windows 10
Graphics card: RTX 2060

Blender Version

Broken: 4.1.0

Short description of error

Hello, I've been exploring Blender's new hair workflow and there's a lot to like. I want to be able to export grooms to Alembic or USD, but it seems the USD exporter currently doesn't include UVs.

Exact steps for others to reproduce the error

Download the Animal fur examples file here: https://www.blender.org/download/demo-files/#hair
Select the Fur - Highland Cattle layer and export to USD.
The resulting USD file does not include a uv/st/UVMap attribute.

**System Information** Operating system: Windows 10 Graphics card: RTX 2060 **Blender Version** Broken: 4.1.0 **Short description of error** Hello, I've been exploring Blender's new hair workflow and there's a lot to like. I want to be able to export grooms to Alembic or USD, but it seems the USD exporter currently doesn't include UVs. **Exact steps for others to reproduce the error** 1. Download the Animal fur examples file here: https://www.blender.org/download/demo-files/#hair 2. Select the Fur - Highland Cattle layer and export to USD. 3. The resulting USD file does not include a uv/st/UVMap attribute.

Brian Hanke added the

labels 2024-03-29 01:07:33 +01:00

Pratik Borhade commented

2024-03-29 06:03:19 +01:00

Hi, thanks for the report. Importing hair curves back to blender imports them in old curve type. I'm not sure if this is expected but attributes are not visible with them. So I checked USDCurvesWriter::do_write, the legacy/old curve type is converted to Curves
cc @deadpin

Did you notice this in usd viewer or after importing in other software?

Hi, thanks for the report. Importing hair curves back to blender imports them in old curve type. I'm not sure if this is expected but attributes are not visible with them. So I checked `USDCurvesWriter::do_write`, the legacy/old curve type is converted to `Curves` cc @deadpin Did you notice this in usd viewer or after importing in other software?

Pratik Borhade added

Status

Needs Information from User

and removed

Status

Needs Triage

labels 2024-03-29 06:03:54 +01:00

Pratik Borhade commented

2024-03-29 06:12:52 +01:00

Even the reader is using all CurvesGeometry functions. Am I doing something wrong 🤔

Brian Hanke commented

2024-03-29 13:34:03 +01:00

@PratikPB2123 Thanks for the reply! I checked the USD export in Houdini Solaris. widths is being exported correctly by Blender, but the UVs are not. They should show up in Houdini as primvars:st. The same issue arises when viewing the exported groom in any other app, including Gaffer or usdview.

(Edited to remove Houdini screenshots.)

@PratikPB2123 Thanks for the reply! I checked the USD export in Houdini Solaris. `widths` is being exported correctly by Blender, but the UVs are not. They should show up in Houdini as `primvars:st`. The same issue arises when viewing the exported groom in any other app, including Gaffer or usdview. (Edited to remove Houdini screenshots.)

👍 1

Gerstmann Bradley commented

2024-03-29 20:34:56 +01:00

@BHGC Hi, posting other software are likely against copyright guideline of blender.
See: https://devtalk.blender.org/t/copyright-guidelines-for-devtalk/17331

Do not:
Include screenshots in posts from commercial / non-open products.
Copy texts, diagrams or other content from websites without their permission.
Indicate in any way that we should copy external ideas or methods without permission.

So I think you have to remove these images before moderators kick in.
On the other hand, you may still speak in common sense about what you observed from other software, etc.

@BHGC Hi, posting other software are likely against copyright guideline of blender. See: https://devtalk.blender.org/t/copyright-guidelines-for-devtalk/17331 >Do not: Include screenshots in posts from commercial / non-open products. Copy texts, diagrams or other content from websites without their permission. Indicate in any way that we should copy external ideas or methods without permission. So I think you have to remove these images before moderators kick in. On the other hand, you may still speak in common sense about what you observed from other software, etc.

👍 1

Jesse Yurkovich commented

2024-03-29 20:57:19 +01:00

This is simply unimplemented currently here for USD and for Alembic (alembic will soon get the ability to export out the new Hair curves but UVs will be missing from the initial implementation as well).

I'll go ahead and confirm so we can track this but, for the future, we generally only track things here that are actual bugs in the implementation. For example, if the UVs were written out but ended up being incorrect in some way etc. There's a lot of things "missing" from various things but we won't typically track them as Issues here.

This is simply unimplemented currently here for USD and for Alembic (alembic will soon get the ability to export out the new Hair curves but UVs will be missing from the initial implementation as well). I'll go ahead and confirm so we can track this but, for the future, we generally only track things here that are actual bugs in the implementation. For example, if the UVs were written out but ended up being incorrect in some way etc. There's a lot of things "missing" from various things but we won't typically track them as Issues here.

Jesse Yurkovich added

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Bug: USD exporter doesn't include hair/curve UVs #120042