Blender Scale problems when export to Unreal #99075

New Issue

Colin Knueppel · 2022-06-22T02:49:51+02:00

Colin Knueppel commented

2022-06-22 02:49:51 +02:00

System Information
Operating system: Windows-10-10.0.22000-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 3080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 512.95

Blender Version
Broken: version: 3.2.0, branch: master, commit date: 2022-06-08 10:22, hash: blender/blender@e05e1e3691
Worked: None that I'm aware of.

Short description of error
If you export a skeletal mesh character to fbx and import it into unreal, the mesh will be the right scale, but the skeleton will be 0.01 the scale. The solution developers have been using is to scale their armature up to 100x, apply scale and then scale it back down to 0.01 before export. This is silly. Blender to Unreal is an increasing common usage, so an option that sets presets that address these issues should be included. Skin and bones should be correct scale and same scale upon import into Unreal.

Exact steps for others to reproduce the error

Rig a character. Ex: subdivide default cube, create armature bone, size armature bone to cube in edit mode and subdivide. Parent cube to armature with automatic weights.
Export fbx of geo and armature.
Import into new project in Unreal 4 or 5.
Select the Physics asset from import and attempt resize of collision volume. Notice that the collision volume manipulation tool wont allow you to go below 0.5 unit radius. Since the skeleton is tiny, you can't properly manipulate the physics volume. Also notice weights of joints are tiny due to assumption of 0.01 scale of joints.

Expected result: Skin and Skeleton should be the same units

**System Information** Operating system: Windows-10-10.0.22000-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 3080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 512.95 **Blender Version** Broken: version: 3.2.0, branch: master, commit date: 2022-06-08 10:22, hash: `blender/blender@e05e1e3691` Worked: None that I'm aware of. **Short description of error** If you export a skeletal mesh character to fbx and import it into unreal, the mesh will be the right scale, but the skeleton will be 0.01 the scale. The solution developers have been using is to scale their armature up to 100x, apply scale and then scale it back down to 0.01 before export. This is silly. Blender to Unreal is an increasing common usage, so an option that sets presets that address these issues should be included. Skin and bones should be correct scale and same scale upon import into Unreal. **Exact steps for others to reproduce the error** 1. Rig a character. Ex: subdivide default cube, create armature bone, size armature bone to cube in edit mode and subdivide. Parent cube to armature with automatic weights. 2. Export fbx of geo and armature. 3. Import into new project in Unreal 4 or 5. 4. Select the Physics asset from import and attempt resize of collision volume. Notice that the collision volume manipulation tool wont allow you to go below 0.5 unit radius. Since the skeleton is tiny, you can't properly manipulate the physics volume. Also notice weights of joints are tiny due to assumption of 0.01 scale of joints. Expected result: Skin and Skeleton should be the same units

Colin Knueppel commented

2022-06-22 02:49:51 +02:00

Added subscriber: @Colin_Knu

Pratik Borhade commented

2022-06-22 05:53:01 +02:00

Added subscriber: @PratikPB2123

Pratik Borhade commented

2022-06-22 05:53:01 +02:00

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

Pratik Borhade commented

2022-06-22 05:53:01 +02:00

Hi, thanks for the report. Did you try exporting with Apply Transform option enabled? (it's an experimental option though)
Maybe problem you've reported here is a known issue: #70161 (FBX I/O Imports and exports objects with wrong scale transform)
Could you confirm if this is the case for you?

Hi, thanks for the report. Did you try exporting with `Apply Transform` option enabled? (it's an experimental option though) Maybe problem you've reported here is a known issue: #70161 (FBX I/O Imports and exports objects with wrong scale transform) Could you confirm if this is the case for you?

Colin Knueppel commented

2022-06-22 14:54:22 +02:00

Epic's Unreal is quickly growing again in the games industry and increasingly used in television, short film and movies. I worry that this should be treated as it's own bug, because this is a very specific workflow that at least tens of thousands of professionals are regularly having to navigate around. A specific solution to this particular workflow may be quicker than addressing the larger issues of the FBX import and export. Considering all that, and that Epic is a corporate level sponsor for Blender, is it that big of an ask that this get treated as a task with its own priority (That other task is almost 3 years old, btw)?

And apply transform did not work.

Epic's Unreal is quickly growing again in the games industry and increasingly used in television, short film and movies. I worry that this should be treated as it's own bug, because this is a very specific workflow that at least tens of thousands of professionals are regularly having to navigate around. A specific solution to this particular workflow may be quicker than addressing the larger issues of the FBX import and export. Considering all that, and that Epic is a corporate level sponsor for Blender, is it that big of an ask that this get treated as a task with its own priority (That other task is almost 3 years old, btw)? And apply transform did not work.

Pratik Borhade commented

2022-06-22 15:41:43 +02:00

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

Pratik Borhade commented

2022-06-23 06:27:39 +02:00

Added subscriber: @mont29

Pratik Borhade commented

2022-06-23 06:27:39 +02:00

In #99075#1378543, @Colin_Knu wrote:
Epic's Unreal is quickly growing again in the games industry and increasingly used in television, short film and movies. I worry that this should be treated as it's own bug, because this is a very specific workflow that at least tens of thousands of professionals are regularly having to navigate around. A specific solution to this particular workflow may be quicker than addressing the larger issues of the FBX import and export. Considering all that, and that Epic is a corporate level sponsor for Blender, is it that big of an ask that this get treated as a task with its own priority (That other task is almost 3 years old, btw)?

And apply transform did not work.

@mont29 Hi, can you comment on this? I don't see any reason to relate this issue with Unreal engine since issue is related to FBX import/export

> In #99075#1378543, @Colin_Knu wrote: > Epic's Unreal is quickly growing again in the games industry and increasingly used in television, short film and movies. I worry that this should be treated as it's own bug, because this is a very specific workflow that at least tens of thousands of professionals are regularly having to navigate around. A specific solution to this particular workflow may be quicker than addressing the larger issues of the FBX import and export. Considering all that, and that Epic is a corporate level sponsor for Blender, is it that big of an ask that this get treated as a task with its own priority (That other task is almost 3 years old, btw)? > > And apply transform did not work. @mont29 Hi, can you comment on this? I don't see any reason to relate this issue with Unreal engine since issue is related to FBX import/export

Colin Knueppel commented

2022-06-23 07:27:12 +02:00

It's directly related to Unreal. I don't know if it shows up in other programs, but I can link you to about half a dozen different forum posts on Unreal sites that are trying to figure out this problem. The issue is very specifically that the blender fbx exports import into Unreal with the skin at one scale and the skeleton at another, and this causes particular problems with physics and socketing attachments in Unreal. This bug report has a very specific scope, unlike the other generic fbx card (that hasn't been fixed for several years).

Omar Emara commented

2022-06-23 10:57:27 +02:00

Closed as duplicate of #47043

Omar Emara closed this issue

2022-06-23 10:57:27 +02:00

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Blender Scale problems when export to Unreal #99075