FBX Exporter: vertices exported in incorrect position causing mesh deformation #61860
Labels
No Label
Interest
Animation & Rigging
Interest
Blender Cloud
Interest
Collada
Interest
Core
Interest
Documentation
Interest
Eevee & Viewport
Interest
Geometry Nodes
Interest
Grease Pencil
Interest
Import and Export
Interest
Modeling
Interest
Modifiers
Interest
Nodes & Physics
Interest
Pipeline, Assets & IO
Interest
Platforms, Builds, Tests & Devices
Interest
Python API
Interest
Rendering & Cycles
Interest
Sculpt, Paint & Texture
Interest
Translations
Interest
User Interface
Interest
UV Editing
Interest
VFX & Video
Meta
Good First Issue
Meta
Papercut
Module
Add-ons (BF-Blender)
Module
Add-ons (Community)
Platform
Linux
Platform
macOS
Platform
Windows
Priority
High
Priority
Low
Priority
Normal
Priority
Unbreak Now!
Status
Archived
Status
Confirmed
Status
Duplicate
Status
Needs Info from Developers
Status
Needs Information from User
Status
Needs Triage
Status
Resolved
Type
Bug
Type
Design
Type
Known Issue
Type
Patch
Type
Report
Type
To Do
No Milestone
No project
No Assignees
5 Participants
Notifications
Due Date
No due date set.
Dependencies
No dependencies set.
Reference: blender/blender-addons#61860
Loading…
Reference in New Issue
Block a user
No description provided.
Delete Branch "%!s()"
Deleting a branch is permanent. Although the deleted branch may continue to exist for a short time before it actually gets removed, it CANNOT be undone in most cases. Continue?
System Information
Operating system: Windows 10 x64
Graphics card: RTX 2070
Blender Version
Broken: 2.79, 2.8
Short description of error
When skinned meshes are exported with FBX 7.4 binary the position of vertices does not export correctly.
As a result meshes are deformed (visible but not extreme in most cases) after export.
Note that external tools/software may be required to compare the meshes as the bug may be invisible upon re-import to blender.
A good way to see the differences is to use the mesh wireframe in iso view in blender versus unity for example.
Comparison of before and after in sample case (Click to load gif)
Exact steps for others to reproduce the error
testcase.blend
Added subscriber: @Tsuna
Added subscriber: @goayakla
Added subscriber: @ZedDB
I can't reproduce this on re-import into blender.
If blender imports the generated file, that means that at least to blender, the positions does not change.
There is not much we can do with simply "it doesn't import correctly in other program".
It may be difficult to see in blender on its own but this is a significant issue as you can not trust blenders export.
This means that the model is deformed in unity, unreal etc when it has been exported from blender (and only from blender).
It's a big deal when any kind of precision is needed.
Added subscriber: @mont29
@mont29 can you reproduce this?
No, cannot reproduce, but I don’t have access to Unity or UE currently.
Re-importing into Blender works as expected, so geometry itself is definitively not altered, issue likely comes from the rigging (binding matrices and all that). Although I would still find it odd that this shows in some other app but not in Blender. FBX works in mysterious ways… :(
{F7651610}So I found a semi viable workaround which is to set pose to rest position until the issue was small enough. This can take anywhere between 1 to 30 attempts. However due to some changes in 2.8 this is not possible anymore.
The mesh always exports in the exact same state. However the incorrect positioning of the verts is more major in 2.8
See attached a testcase for 2.8
Added subscriber: @iss
Changed status from 'Confirmed' to: 'Needs User Info'
I have re-triaged this report and can not reproduce it.
Can you please check if this is still an issue in latest build?
https://builder.blender.org/download/
@iss Tested with 2.83 Alpha .
Able to reproduce the issue.
For safety i also tried entering pose mode and applying pose to rest.
Same result as previously.
Verified in 3dsMax 2020, Unity 2019.2.4 and Unity 2017.4.28<
The incorrect deformation is identical in all 3 instances.
Changed status from 'Needs User Info' to: 'Confirmed'