Cube projection size parameter is wrong #85379

New Issue

Ludvik Koutny · 2021-02-04T17:32:58+01:00

Ludvik Koutny commented

2021-02-04 17:32:58 +01:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce GTX 1080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 461.09

Blender Version
Broken: version:

2.93.0
2.92.0
2.91.0, branch: master (modified), commit date: 2020-11-25 11:06, hash: b50598bc78
Worked: Never

Short description of error
When using Cube projection UV mapping operator, the resulting cubic projection size is actually double of the size displayed in the user interface. So when you perform a cube projection with the size 1.0, which would imply a cube of a size of 1 blender unit, which should be 1 meter, but size of the cubic projection actually ends up 2 meters wide. This is probably remnant of the old weird times when cube primitive in Blender was specified using a radius value instead of size value.

Exact steps for others to reproduce the error

In an empty .blend file, create a new cube
Resize the cube so that the dimensions are 1x1x1 meters and apply the scale
In edit mode, select all the cube faces and run Cube projection UV operator, and set the Cube Size to 1.0
Result: In the UV editor, the cube UV faces do not match the edges of UV space perfectly despite the size of the 3D cube in the viewport matching the Cube Size value set in Cube Projection operator.
Expected. The UV faces in the editor match the edges of the UV space perfectly, since a Cube Projection with a size of 1.0 was applied on a Cube mesh with a size of 1.0 and 1.0 scale transform.

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: GeForce GTX 1080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 461.09 **Blender Version** Broken: version: - 2.93.0 - 2.92.0 - 2.91.0, branch: master (modified), commit date: 2020-11-25 11:06, hash: `b50598bc78` Worked: Never **Short description of error** When using Cube projection UV mapping operator, the resulting cubic projection size is actually double of the size displayed in the user interface. So when you perform a cube projection with the size 1.0, which would imply a cube of a size of 1 blender unit, which should be 1 meter, but size of the cubic projection actually ends up 2 meters wide. This is probably remnant of the old weird times when cube primitive in Blender was specified using a radius value instead of size value. **Exact steps for others to reproduce the error** 1. In an empty .blend file, create a new cube 2. Resize the cube so that the dimensions are 1x1x1 meters and apply the scale 3. In edit mode, select all the cube faces and run Cube projection UV operator, and set the Cube Size to 1.0 Result: In the UV editor, the cube UV faces do not match the edges of UV space perfectly despite the size of the 3D cube in the viewport matching the Cube Size value set in Cube Projection operator. Expected. The UV faces in the editor match the edges of the UV space perfectly, since a Cube Projection with a size of 1.0 was applied on a Cube mesh with a size of 1.0 and 1.0 scale transform.

Ludvik Koutny commented

2021-02-04 17:32:58 +01:00

Added subscriber: @Rawalanche

Robert Guetzkow commented

2021-02-05 11:45:26 +01:00

Added subscriber: @rjg

Robert Guetzkow commented

2021-02-05 11:45:26 +01:00

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

Robert Guetzkow commented

2021-02-05 11:45:26 +01:00

I can confirm this issue. It seems this needs adjustments in both cube_project_exec and uvedit_unwrap_cube_project.

When the cube_size is determined based on the bounds it shouldn't use cube_size = cube_size ? 2.0f / cube_size : 1.0f; in cube_project_exec. Instead the cube_size should be used as is (or set to 1.0f if zero).

The uvedit_unwrap_cube_project shouldn't need to multiply the cube_size with a 0.5f factor anymore.

I can confirm this issue. It seems this needs adjustments in both `cube_project_exec` and `uvedit_unwrap_cube_project`. When the `cube_size` is determined based on the `bounds` it shouldn't use `cube_size = cube_size ? 2.0f / cube_size : 1.0f;` in `cube_project_exec`. Instead the `cube_size` should be used as is (or set to `1.0f` if zero). The `uvedit_unwrap_cube_project` shouldn't need to multiply the `cube_size` with a `0.5f` factor anymore.

Ludvik Koutny commented

2021-03-01 15:10:42 +01:00

@rjg

Hi,
any reason this was not addressed and made it into final 2.92?

@rjg Hi, any reason this was not addressed and made it into final 2.92?

Robert Guetzkow commented

2021-03-01 15:33:31 +01:00

@Rawalanche Nobody wrote a patch for it between the confirmation of the bug (Feb 5) and release of 2.92 (Feb 25).

Robert Guetzkow self-assigned this 2021-03-01 15:34:26 +01:00

Ludvik Koutny commented

2021-03-01 18:01:14 +01:00

In #85379#1121496, @rjg wrote:
@Rawalanche Nobody wrote a patch for it between the confirmation of the bug (Feb 5) and release of 2.92 (Feb 25).

I was really confused mainly because right in the post above mine it seemed like you already had a solution, knew exactly what needs to be done, and at the same time it was reported three weeks before release, so time should be there. So I thought there was some deeper dependency on something else preventing this from being addressed.

> In #85379#1121496, @rjg wrote: > @Rawalanche Nobody wrote a patch for it between the confirmation of the bug (Feb 5) and release of 2.92 (Feb 25). I was really confused mainly because right in the post above mine it seemed like you already had a solution, knew exactly what needs to be done, and at the same time it was reported three weeks before release, so time should be there. So I thought there was some deeper dependency on something else preventing this from being addressed.

Robert Guetzkow commented

2021-03-01 18:24:32 +01:00

@Rawalanche No hidden surprise so far. Since the beginning of February I'm no longer working part-time on the bug tracker , because I have to finish my computer science degree. Thus I have limited time available to write patches and help with bug triaging.

@Rawalanche No hidden surprise so far. Since the beginning of February I'm [no longer working part-time on the bug tracker ](https://devtalk.blender.org/t/1-february-2021/17225), because I have to finish my computer science degree. Thus I have limited time available to write patches and help with bug triaging.

blender-admin commented

2022-05-03 05:21:44 +02:00

This issue was referenced by 8810d0cecd

This issue was referenced by 8810d0cecdd5c192d0562c62490695d22ca684d5

Campbell Barton commented

2022-05-03 05:27:30 +02:00

Changed status from 'Confirmed' to: 'Resolved'

Campbell Barton closed this issue

2022-05-03 05:27:30 +02:00

Ludvik Koutny commented

2022-06-17 16:31:39 +02:00

It doesn't appear that https://developer.blender.org/rB8810d0cecdd5c192d0562c62490695d22ca684d5 fixed anything. Applying a cube projection of a size of 2 onto a 2x2x2 cube with 1.0 scale will still result in cubic mapping of size 1:

The fix either did not make it into the main branch or it's a placebo.

It doesn't appear that https://developer.blender.org/rB8810d0cecdd5c192d0562c62490695d22ca684d5 fixed anything. Applying a cube projection of a size of 2 onto a 2x2x2 cube with 1.0 scale will still result in cubic mapping of size 1: ![image.png](https://archive.blender.org/developer/F13179236/image.png) ![image.png](https://archive.blender.org/developer/F13179239/image.png) The fix either did not make it into the main branch or it's a placebo.

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Cube projection size parameter is wrong #85379