object.to_mesh ignores object.update_from_editmode #63244

New Issue

Mikhail Rachinskiy · 2019-04-03T11:47:38+02:00

2019-04-03 11:47:38 +02:00

System Information
Operating system: Windows-10-10.0.17134 64 Bits
Graphics card: GeForce GTX 860M/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 417.35

Blender Version
Broken: version: 2.80 (sub 53), branch: blender2.7, commit date: 2019-04-02 19:53, hash: a813e259d6
Worked: This might be the cause 46eb5a0b8a

Short description of error
obj.update_from_editmode updates obj.data but not the result of the obj.to_mesh as it was before.

bmesh.from_object also does not update, but it did not work before unlike to_mesh.

Why there is no easy way of getting evaluated mesh from edit mode? depsgraph.id_eval_get(obj).data works only from object mode, and to_mesh creates a whole new mesh datablock which I don't need.

Exact steps for others to reproduce the error

Open attached blend file: ob_update.blend
Run the script from Text Editor > popup shows up which tells there is 1 selected face.
No matter how you change the face selection in 3D view, it will always show 1 face selected, unless you leave and re-enter edit mode.

**System Information** Operating system: Windows-10-10.0.17134 64 Bits Graphics card: GeForce GTX 860M/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 417.35 **Blender Version** Broken: version: 2.80 (sub 53), branch: blender2.7, commit date: 2019-04-02 19:53, hash: `a813e259d6` Worked: This might be the cause 46eb5a0b8a **Short description of error** `obj.update_from_editmode` updates `obj.data` but not the result of the `obj.to_mesh` as it was before. `bmesh.from_object` also does not update, but it did not work before unlike `to_mesh`. Why there is no easy way of getting evaluated mesh from edit mode? `depsgraph.id_eval_get(obj).data` works only from object mode, and `to_mesh` creates a whole new mesh datablock which I don't need. **Exact steps for others to reproduce the error** - Open attached blend file: [ob_update.blend](https://archive.blender.org/developer/F6908776/ob_update.blend) - Run the script from Text Editor > popup shows up which tells there is `1` selected face. - No matter how you change the face selection in 3D view, it will always show `1` face selected, unless you leave and re-enter edit mode.

Mikhail Rachinskiy commented

2019-04-03 11:47:38 +02:00

Added subscriber: @MikhailRachinskiy

Sergey Sharybin was assigned by Sebastian Parborg

2019-04-03 13:11:49 +02:00

takeshi funahashi commented

2019-04-04 07:03:21 +02:00

Added subscriber: @TakeshiFunahashi

Jose Conseco commented

2019-04-05 11:54:20 +02:00

Added subscriber: @JoseConseco

MACHIN3 commented

2019-04-06 22:28:10 +02:00

Added subscriber: @MACHIN3

Sergey Sharybin commented

2019-04-09 12:11:10 +02:00

Added subscriber: @brecht

Sergey Sharybin commented

2019-04-09 12:11:10 +02:00

In order to properly get mesh with modifier applies the dependency graph is to be evaluated first. What happens in this script is that it does modify the original object (by doing update_from_editmode), but it does not inform dependency graph about it. There are two ways to go about it:

Tag object for update and make sure the dependency graph is re-evaluated by calling this after update_from_editmode:

ob.update_tag()
bpy.context.view_layer.update()

Request mesh without modifiers applied, by doing me = ob.to_mesh(bpy.context.depsgraph, False)

@brecht, do you think there is some way we should improve/change API here, or add some sanity checks?

In order to properly get mesh with modifier applies the dependency graph is to be evaluated first. What happens in this script is that it does modify the original object (by doing `update_from_editmode`), but it does not inform dependency graph about it. There are two ways to go about it: 1. Tag object for update and make sure the dependency graph is re-evaluated by calling this after `update_from_editmode`: ``` ob.update_tag() bpy.context.view_layer.update() ``` 2. Request mesh without modifiers applied, by doing `me = ob.to_mesh(bpy.context.depsgraph, False)` @brecht, do you think there is some way we should improve/change API here, or add some sanity checks?

Mikhail Rachinskiy commented

2019-04-10 12:10:42 +02:00

This change in behaviour could be mentioned in 2.80 Py API Changes .
I will also create Q&A on stackexchange.
This might be enough to keep people informed.

This change in behaviour could be mentioned in [2.80 Py API Changes ](https://wiki.blender.org/wiki/Reference/Release_Notes/2.80/Python_API). I will also create Q&A on stackexchange. This might be enough to keep people informed.

Sergey Sharybin commented

2019-04-10 15:50:33 +02:00

@MikhailRachinskiy, agree. There is still a huge work to be done on documentation and release logs, and this indeed something what should be mentioned there.

takeshi funahashi commented

2019-04-10 17:30:25 +02:00

I really thanks Mikhail make this report, and Sergey offer way how to up-date correctly.

There seems case, even though I do not use "update_from_editmode",
I need to add "ob.update_tag() bpy.context.view_layer.update()" in sipite of "ob.data.update()"
After that, function, which overwrite shape key data, suddenly work again.
(it seems break after this commit)

def apply_vert_coords(ob, mesh, x):
    for i, v in enumerate(mesh):
        v.co = x[i]
    ob.update_tag() 
    bpy.context.view_layer.update()
    ob.data.update()

The "mesh" argument is, active_shape_ key.data of object.
then x = editted vertices with use object_to.mesh()

I still not clear understand when I actually need to use Sargey Recommend way.
then hope new API document follow these detail too.

I really thanks Mikhail make this report, and Sergey offer way how to up-date correctly. There seems case, even though I do not use "update_from_editmode", I need to add "ob.update_tag() bpy.context.view_layer.update()" in sipite of "ob.data.update()" After that, function, which overwrite shape key data, suddenly work again. (it seems break after this commit) ``` def apply_vert_coords(ob, mesh, x): for i, v in enumerate(mesh): v.co = x[i] ob.update_tag() bpy.context.view_layer.update() ob.data.update() ``` The "mesh" argument is, active_shape_ key.data of object. then x = editted vertices with use object_to.mesh() I still not clear understand when I actually need to use Sargey Recommend way. then hope new API document follow these detail too.

Sergey Sharybin commented

2019-05-27 11:32:53 +02:00

Changed status from 'Open' to: 'Resolved'

Sergey Sharybin closed this issue

2019-05-27 11:32:53 +02:00

Sergey Sharybin commented

2019-05-27 11:32:53 +02:00

Committed extra changes in d4f12860aa which makes this usecase a bit more simple.

Here is a script ported to all the recent dependency graph API changes.

import bpy

ob = bpy.context.object
ob.update_from_editmode()

depsgraph = bpy.context.evaluated_depsgraph_get()
ob_eval = ob.evaluated_get(depsgraph)

me = ob_eval.to_mesh()
i = len([poly for poly in me.polygons if poly.select])
ob_eval.to_mesh_clear()

def draw(self, context):
    self.layout.label(text=str(i))

bpy.context.window_manager.popup_menu(draw, title="Faces selected")

Thanks for the report, considering it solved now.

Committed extra changes in d4f12860aa which makes this usecase a bit more simple. Here is a script ported to all the recent dependency graph API changes. ``` import bpy ob = bpy.context.object ob.update_from_editmode() depsgraph = bpy.context.evaluated_depsgraph_get() ob_eval = ob.evaluated_get(depsgraph) me = ob_eval.to_mesh() i = len([poly for poly in me.polygons if poly.select]) ob_eval.to_mesh_clear() def draw(self, context): self.layout.label(text=str(i)) bpy.context.window_manager.popup_menu(draw, title="Faces selected") ``` Thanks for the report, considering it solved now.

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object.to_mesh ignores object.update_from_editmode #63244