Get face map values in edit mode #85398

New Issue

Sergey · 2021-02-05T11:43:34+01:00

Sergey commented

2021-02-05 11:43:34 +01:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: Intel(R) HD Graphics 630 Intel 4.5.0 - Build 25.20.100.6471

Blender Version
Broken: version: 2.91.0, branch: master, commit date: 2020-11-25 08:34, hash: 0f45cab862

Short description of error
I'm trying utilize face maps. The question is that I can't get actual face map status from polygons when a mesh is in edit mode. As far as I know there is no such problem with other mesh attributes. At least active material can be definitely received from mesh in edit mode. Is it bug or limitation?
2021-02-05 14-33-00.mp4

Exact steps for others to reproduce the error

test.blend

Dowload file
Run script
Get into edit mode
Change face map set
Run script again
Compare prints in cosole - there should not be difference

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: Intel(R) HD Graphics 630 Intel 4.5.0 - Build 25.20.100.6471 **Blender Version** Broken: version: 2.91.0, branch: master, commit date: 2020-11-25 08:34, hash: `0f45cab862` **Short description of error** I'm trying utilize face maps. The question is that I can't get actual `face map` status from polygons when a mesh is in edit mode. As far as I know there is no such problem with other mesh attributes. At least `active material` can be definitely received from mesh in edit mode. Is it bug or limitation? [2021-02-05 14-33-00.mp4](https://archive.blender.org/developer/F9651432/2021-02-05_14-33-00.mp4) **Exact steps for others to reproduce the error** [test.blend](https://archive.blender.org/developer/F9651480/test.blend) 1. Dowload file 2. Run script 3. Get into edit mode 4. Change face map set 5. Run script again 6. Compare prints in cosole - there should not be difference

Sergey commented

2021-02-05 11:43:34 +01:00

Added subscriber: @randum

Philipp Oeser commented

2021-02-05 13:52:27 +01:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2021-02-05 13:52:27 +01:00

You have to read this from the evaluated object like so:

import bpy
import bmesh

depsgraph = bpy.context.evaluated_depsgraph_get()
object_eval = bpy.context.active_object.evaluated_get(depsgraph)
me_eval = object_eval.to_mesh()

bm = bmesh.new()
bm.from_mesh(me_eval)
object_eval.to_mesh_clear()

l = bm.faces.layers.face_map.active
print([f[l] for f in bm.faces])
bm.free()

test_corrected.blend

You have to read this from the evaluated object like so: ``` import bpy import bmesh depsgraph = bpy.context.evaluated_depsgraph_get() object_eval = bpy.context.active_object.evaluated_get(depsgraph) me_eval = object_eval.to_mesh() bm = bmesh.new() bm.from_mesh(me_eval) object_eval.to_mesh_clear() l = bm.faces.layers.face_map.active print([f[l] for f in bm.faces]) bm.free() ``` [test_corrected.blend](https://archive.blender.org/developer/F9654181/test_corrected.blend)

Philipp Oeser commented

2021-02-05 14:03:07 +01:00

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

Philipp Oeser closed this issue

2021-02-05 14:03:07 +01:00

Philipp Oeser self-assigned this 2021-02-05 14:03:07 +01:00

Philipp Oeser commented

2021-02-05 14:03:07 +01:00

Afaict, this is not a bug, see here also https://docs.blender.org/api/master/bpy.types.Depsgraph.html

Will close (but feel free to comment again if issues persist -- or if you really think this is an exception to how blenders python API works in other areas [what I havent checked is what you mentioned with active material since this is not in face.layers?] -- we can always repoen in this case)

Afaict, this is not a bug, see here also https://docs.blender.org/api/master/bpy.types.Depsgraph.html Will close (but feel free to comment again if issues persist -- or if you really think this is an exception to how blenders python API works in other areas [what I havent checked is what you mentioned with `active material` since this is not in face.layers?] -- we can always repoen in this case)

Sergey commented

2021-02-05 16:15:31 +01:00

I was basing on documentation of getting access to bmesh layers (https://docs.blender.org/api/current/bmesh.html#customdata-access) in my attempt.

In the examples there is nothing about necessity of evaluating depsgraph. I've tried getting access to weights of a vertices group in edit mode and was succeeded without calling depsgraph.

Also it described in the documentation that depsfraph should be used only to get data with applied animation, drivers, modifiers and constrains and there is nothing about face maps or other mesh attributes.

It seems to me that either documentation is not accurate about using face maps or face maps really behave their selves inadequate compared to other mesh attributes.

I was basing on documentation of getting access to `bmesh` layers (https://docs.blender.org/api/current/bmesh.html#customdata-access) in my attempt. In the examples there is nothing about necessity of evaluating `depsgraph`. I've tried getting access to weights of a vertices group in edit mode and was succeeded without calling depsgraph. Also it described in the documentation that `depsfraph` should be used only to get data with applied animation, drivers, modifiers and constrains and there is nothing about face maps or other mesh attributes. It seems to me that either documentation is not accurate about using face maps or face maps really behave their selves inadequate compared to other mesh attributes.

Philipp Oeser commented

2021-02-10 18:27:16 +01:00

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

Philipp Oeser reopened this issue

2021-02-10 18:27:16 +01:00

Philipp Oeser commented

2021-02-10 18:27:16 +01:00

Needs another look

Germano Cavalcante commented

2021-07-27 16:05:39 +02:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2021-07-27 16:05:39 +02:00

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

Germano Cavalcante closed this issue

2021-07-27 16:05:39 +02:00

Germano Cavalcante commented

2021-07-27 16:05:39 +02:00

While in edit mode, the object's mesh (object.data) is not updated.
Only BMesh, Mesh Cage and Mesh Final are updated.
You have to copy the BMesh from the Mesh (bmesh.from_edit_mesh(me))

This is known behavior and not considered a bug.
It's preferable that way for performance.

While in edit mode, the object's mesh (`object.data`) is not updated. Only BMesh, Mesh Cage and Mesh Final are updated. You have to copy the `BMesh` from the `Mesh` (`bmesh.from_edit_mesh(me)`) This is known behavior and not considered a bug. It's preferable that way for performance.

Sergey commented

2021-07-28 06:20:37 +02:00

I've tried to use from_edit_mesh method and it works but only once. The second attempt always lead to a crash. Am I doing something wrong? Should I open another task with crash report?

test.blend

2021-07-28 08-13-58.mp4

I've tried to use `from_edit_mesh` method and it works but only once. The second attempt always lead to a crash. Am I doing something wrong? Should I open another task with crash report? [test.blend](https://archive.blender.org/developer/F10242265/test.blend) [2021-07-28 08-13-58.mp4](https://archive.blender.org/developer/F10242263/2021-07-28_08-13-58.mp4)

Debuk commented

2021-07-28 08:52:28 +02:00

Added subscriber: @Debuk

Debuk commented

2021-07-28 08:52:28 +02:00

Make a copy of it or dont free it

bm = bmesh.from_edit_mesh(me).copy()

https://docs.blender.org/api/current/bmesh.types.html#bmesh.types.BMesh.free

Make a copy of it or dont free it ``` bm = bmesh.from_edit_mesh(me).copy() ``` https://docs.blender.org/api/current/bmesh.types.html#bmesh.types.BMesh.free

Sergey commented

2021-07-28 08:59:35 +02:00

@Debuk Thanks. Now it works as expected.

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Get face map values in edit mode #85398