Sculpt: Extract Face Set command only works correctly if the BVH is rebuild #85136

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TheRedWaxPolice · 2021-01-28T03:43:00+01:00

TheRedWaxPolice commented

2021-01-28 03:43:00 +01:00

System Information
Operating system: Win 10

Blender Version
Broken: blender-2.92.0-198980693ba7-windows64
Worked: Never?

Short description of error
Not sure if it's a bug or limitation but it looks like the "Extract Face Set" command only works correctly if the BVH is rebuild, otherwise it will only extract the shape of the original mesh, discarding the deformations...

Exact steps for others to reproduce the error
File > New > Sculpting...
Deform the sphere with any brush...
Create a face set on those deformed parts...
Go to Face Sets > Extract Face Set, then choose the face set you just created...
The result: The mesh extraction process didn't take into consideration the deformed mesh, instead it extracted the shape of the original sphere before the deformation...

See:
2021-01-27_23-27-33.mp4

Now, if you repeat the same steps but before extracting you choose Sculpt > Rebuild BVH, then it will work as expected... i.e.
File > New > Sculpting...
Deform the sphere with any brush...
Create a face set on those deformed parts...
Sculpt > Rebuild BVH
Face Sets > Extract Face Set, then choose the face set you just created...
Result: As expected (the deformed parts are extracted correctly)...

See:
2021-01-27_23-30-04.mp4

**System Information** Operating system: Win 10 **Blender Version** Broken: blender-2.92.0-198980693ba7-windows64 Worked: Never? **Short description of error** Not sure if it's a bug or limitation but it looks like the "Extract Face Set" command only works correctly if the BVH is rebuild, otherwise it will only extract the shape of the original mesh, discarding the deformations... **Exact steps for others to reproduce the error** File > New > Sculpting... Deform the sphere with any brush... Create a face set on those deformed parts... Go to Face Sets > Extract Face Set, then choose the face set you just created... The result: The mesh extraction process didn't take into consideration the deformed mesh, instead it extracted the shape of the original sphere before the deformation... See: [2021-01-27_23-27-33.mp4](https://archive.blender.org/developer/F9601753/2021-01-27_23-27-33.mp4) ___ Now, if you repeat the same steps but before extracting you choose Sculpt > Rebuild BVH, then it will work as expected... i.e. File > New > Sculpting... Deform the sphere with any brush... Create a face set on those deformed parts... Sculpt > Rebuild BVH Face Sets > Extract Face Set, then choose the face set you just created... Result: As expected (the deformed parts are extracted correctly)... See: [2021-01-27_23-30-04.mp4](https://archive.blender.org/developer/F9601771/2021-01-27_23-30-04.mp4)

TheRedWaxPolice commented

2021-01-28 03:43:00 +01:00

Added subscriber: @TheRedWaxPolice