Geometry Node: Sculpt mode doesn't cause update due to editing #103871

New Issue

Daniel Ulrich · 2023-01-14T00:39:37+01:00

Daniel Ulrich commented

2023-01-14 00:39:37 +01:00

SIMPLE REPORT:

System Information
Operating system: Windows-10-10.0.19045-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 527.56

Blender Version
Broken: version: 3.5.0 Alpha, branch: master, commit date: 2023-01-08 22:09, hash: e7a554e551
Worked: Never

Short description of error

Objects with geometry nodes do not update if dependent on the object that is currently being sculpted.

2023-01-14 13-13-37.mp4

Exact steps for others to reproduce the error

Duplicete default cube.
Add Geometry Node tree on copy, add Object Info, choose other one cube, connect geometry to group output.
Select other one cube, go to sculpt mode, do anything.
Cube with geometry node does not according to sculpted one

USER REPORT:

System Information
Operating system: Windows 10 Pro
Graphics card: Geforece RTX 2080

Blender Version
Broken: 3.4.1 Stable
Worked: not sure

Geometry nodes network is not updating when in sculpt mode. It's updating fine when in edit mode.

I have nodes basically adding differences in point positions from one mesh to another -

sculpt_mode_update.blend

Create an object(=A) and add a geometry nodes modifier
Duplicate the object(=B), and use it's object info in the first objects geometry node
Connect object B geometry, position and ID into a sample index node, sampling a vector on a point
Subtract the vector coming from the sample index from object A's position
Connect the result to the offset
Try moving verts on object B in edit mode and see object A updating
Try moving verts on object B in sculpt mode. Object A is only updating when switching from sculpt mode back to object mode.

Based on the default startup or an attached .blend file (as simple as possible).

## SIMPLE REPORT: **System Information** Operating system: Windows-10-10.0.19045-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 527.56 **Blender Version** Broken: version: 3.5.0 Alpha, branch: master, commit date: 2023-01-08 22:09, hash: `e7a554e551` Worked: Never **Short description of error** Objects with geometry nodes do not update if dependent on the object that is currently being sculpted. [2023-01-14 13-13-37.mp4](https://archive.blender.org/developer/F14149477/2023-01-14_13-13-37.mp4) **Exact steps for others to reproduce the error** 1. Duplicete default cube. 2. Add Geometry Node tree on copy, add `Object Info`, choose other one cube, connect geometry to group output. 3. Select other one cube, go to sculpt mode, do anything. Cube with geometry node does not according to sculpted one ## USER REPORT: **System Information** Operating system: Windows 10 Pro Graphics card: Geforece RTX 2080 **Blender Version** Broken: 3.4.1 Stable Worked: not sure Geometry nodes network is not updating when in sculpt mode. It's updating fine when in edit mode. I have nodes basically adding differences in point positions from one mesh to another - ![liveconnectionSculpt.gif](https://archive.blender.org/developer/F14148913/liveconnectionSculpt.gif) ![liveconnectionEdit.gif](https://archive.blender.org/developer/F14148912/liveconnectionEdit.gif) [sculpt_mode_update.blend](https://archive.blender.org/developer/F14148911/sculpt_mode_update.blend) ![Screenshot 2023-01-14 120957.png](https://archive.blender.org/developer/F14148910/Screenshot_2023-01-14_120957.png) - Create an object(=A) and add a geometry nodes modifier - Duplicate the object(=B), and use it's object info in the first objects geometry node - Connect object B geometry, position and ID into a sample index node, sampling a vector on a point - Subtract the vector coming from the sample index from object A's position - Connect the result to the offset - Try moving verts on object B in edit mode and see object A updating - Try moving verts on object B in sculpt mode. Object A is only updating when switching from sculpt mode back to object mode. Based on the default startup or an attached .blend file (as simple as possible).

👀 1

Daniel Ulrich commented

2023-01-14 00:39:37 +01:00

Added subscriber: @dan2

Iliya Katushenock changed title from ~~geometry nodes sculpt mode update~~ to Geometry Node: Sculpt mode doesn't cause update due to editing

2023-01-14 11:22:30 +01:00

Iliya Katushenock commented

2023-01-14 11:23:24 +01:00

Added subscriber: @mod_moder

Iliya Katushenock commented

2023-01-14 11:23:24 +01:00

Hello. After looking into this a bit, it seems that all modifiers ignore actions in sculpt mode. Most likely, it's just some kind of limitation.

Daniel Ulrich commented

2023-01-14 11:42:04 +01:00

Do they? Several modifiers do update just fine in sculpt mode, from subdivision surface over wireframe to bevel.

I've also used several geo nodes setups in sculpt mode without issues.

Do they? Several modifiers do update just fine in sculpt mode, from subdivision surface over wireframe to bevel. I've also used several geo nodes setups in sculpt mode without issues.

Iliya Katushenock commented

2023-01-14 12:04:10 +01:00

It is worth considering that different groups of modifiers have real technical meaning.
If you're just deforming the geometry, then it's easier than interpreting the sculpt for the generators.
So yeah, there's a lot to think about...

![image.png](https://archive.blender.org/developer/F14149526/image.png) It is worth considering that different groups of modifiers have real technical meaning. If you're just deforming the geometry, then it's easier than interpreting the sculpt for the generators. So yeah, there's a lot to think about...

Daniel Ulrich commented

2023-01-14 19:48:30 +01:00

Absolutely, I understand this to be a complex subject.

It may be worth mentioning that submitting this as a bug report was suggested by Hans Goudey, after I asked about it on a community forum.

link to the forum thread

Absolutely, I understand this to be a complex subject. It may be worth mentioning that submitting this as a bug report was suggested by Hans Goudey, after I asked about it on a community forum. [link to the forum thread ](https://blenderartists.org/t/geometry-nodes-sculpt-mode-mesh-update/1444005/2)

Iliya Katushenock commented

2023-01-14 19:52:19 +01:00

Well, I'm not sure about other modifiers, but geometry nodes worked like that back in 3.1

Daniel Ulrich commented

2023-01-14 19:59:37 +01:00

Some nodes in geometry nodes, that is. Depending on the nodes used, updating seems to be working fine.

I think I get it now, it's just about how and when the object info is passed along in the modfier.

Just my two cents here, but since this can have a common use case of deforming a mesh in sculpt mode, and at the same time seeing the scalp mesh and groom updating, I'd say this might be worth looking into further.

Some nodes in geometry nodes, that is. Depending on the nodes used, updating seems to be working fine. I think I get it now, it's just about how and when the object info is passed along in the modfier. Just my two cents here, but since this can have a common use case of deforming a mesh in sculpt mode, and at the same time seeing the scalp mesh and groom updating, I'd say this might be worth looking into further.

Iliya Katushenock commented

2023-01-14 20:37:36 +01:00

Changed status from 'Needs Triage' to: 'Needs Developer To Reproduce'

Iliya Katushenock commented

2023-01-14 20:37:36 +01:00

Added subscriber: @HooglyBoogly

Hans Goudey commented

2023-02-07 04:03:15 +01:00

I don't think this is the intended behavior, but I think it points to a deeper architectural flaw in Blender.

The behavior can be fixed with this change:

diff --git a/source/blender/editors/sculpt_paint/sculpt.cc b/source/blender/editors/sculpt_paint/sculpt.cc
index b5d3e53b00c..de0d3cf5dcf 100644
--- a/source/blender/editors/sculpt_paint/sculpt.cc
+++ b/source/blender/editors/sculpt_paint/sculpt.cc
@@ -5390,7 +5390,7 @@ void SCULPT_flush_update_step(bContext *C, SculptUpdateType update_flags)
 
   /* Only current viewport matters, slower update for all viewports will
    * be done in sculpt_flush_update_done. */
-  if (!BKE_sculptsession_use_pbvh_draw(ob, rv3d)) {
+  if (true || !BKE_sculptsession_use_pbvh_draw(ob, rv3d)) {
     /* Slow update with full dependency graph update and all that comes with it.
      * Needed when there are modifiers or full shading in the 3D viewport. */
     DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);

That will have a performance impact though. It seems like this BKE_sculptsession_use_pbvh_draw is in the wrong place. I think we should be able to do a full ID_RECALC_GEOMETRY depsgraph update, which should only end up being expensive if there are modifiers or other objects depending on the data. The depsgraph reevaluation might be slow or it might be fast, that would depend on other factors.
I'm guessing Sergey or Brecht would have thought about this in the past, I'm curious about their opinions here.

I don't think this is the intended behavior, but I think it points to a deeper architectural flaw in Blender. The behavior can be fixed with this change: ```Diff diff --git a/source/blender/editors/sculpt_paint/sculpt.cc b/source/blender/editors/sculpt_paint/sculpt.cc index b5d3e53b00c..de0d3cf5dcf 100644 --- a/source/blender/editors/sculpt_paint/sculpt.cc +++ b/source/blender/editors/sculpt_paint/sculpt.cc @@ -5390,7 +5390,7 @@ void SCULPT_flush_update_step(bContext *C, SculptUpdateType update_flags) /* Only current viewport matters, slower update for all viewports will * be done in sculpt_flush_update_done. */ - if (!BKE_sculptsession_use_pbvh_draw(ob, rv3d)) { + if (true || !BKE_sculptsession_use_pbvh_draw(ob, rv3d)) { /* Slow update with full dependency graph update and all that comes with it. * Needed when there are modifiers or full shading in the 3D viewport. */ DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY); ``` That will have a performance impact though. It seems like this `BKE_sculptsession_use_pbvh_draw` is in the wrong place. I think we should be able to do a full `ID_RECALC_GEOMETRY` depsgraph update, which should only end up being expensive if there are modifiers or other objects depending on the data. The depsgraph reevaluation might be slow or it might be fast, that would depend on other factors. I'm guessing Sergey or Brecht would have thought about this in the past, I'm curious about their opinions here.

Philipp Oeser removed the

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Geometry Node: Sculpt mode doesn't cause update due to editing #103871

SIMPLE REPORT:

USER REPORT: