blender/blender

Some modifiers affect sculpting brushes (normals not updating) #114692

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opened 2023-11-10 08:06:53 +01:00 by renderluz · 8 comments

renderluz commented

2023-11-10 08:06:53 +01:00

System Information
Operating system: Window11
Graphics card: Gforce 1080

Blender Version
Broken: Blender 4.0.0 Release Candidate
Worked: Blender 3.6.5

Caused by 5af8b839cf

Short description of error
If particular modifiers are present, sculpting normals wont update
Problem is that modifiers of type eModifierTypeType_NonGeometrical will still result in the PBVH being considered pbvh->deformed

Affected modifiers:

Geometry Nodes
UV Project
Smooth by Angle
UVWarp
VertexWeightEdit
VertexWeightMix

Exact steps for others to reproduce the error

add a plane with plenty subdivisions (e.g. 50 -- to see normals on sculpting)
enter sculptmode
sculpt (normals properly updating)
add an empty geometry nodes modifier (or any of the above mentioned modifiers)
sculpt again (normals dont update properly anymore)

Original report

If I have a cube with the Uv project on in the viewport and I try to sculpt
the brushes behave weirdly like they pull the vertices too much.

Create a cube add a Uv project modifier, remesh it inside the sculpt mode using ctr+r
try to use the scrape brush to flatten an area or the Clay strip, the way they behave should
look odd right away.

**System Information** Operating system: Window11 Graphics card: Gforce 1080 **Blender Version** Broken: Blender 4.0.0 Release Candidate Worked: Blender 3.6.5 Caused by 5af8b839cfc6e3e93869ab6371f2f3c94d35136f **Short description of error** If particular modifiers are present, sculpting normals wont update Problem is that modifiers of type eModifierTypeType_NonGeometrical will still result in the PBVH being considered pbvh->deformed Affected modifiers: - Geometry Nodes - UV Project - Smooth by Angle - UVWarp - VertexWeightEdit - VertexWeightMix **Exact steps for others to reproduce the error** - add a plane with plenty subdivisions (e.g. 50 -- to see normals on sculpting) - enter sculptmode - sculpt (normals properly updating) - add an empty geometry nodes modifier (or any of the above mentioned modifiers) - sculpt again (normals dont update properly anymore) **Original report** If I have a cube with the Uv project on in the viewport and I try to sculpt the brushes behave weirdly like they pull the vertices too much. Create a cube add a Uv project modifier, remesh it inside the sculpt mode using ctr+r try to use the scrape brush to flatten an area or the Clay strip, the way they behave should look odd right away.

65 KiB

expected behavior.png

91 KiB

expected behavior.png

renderluz added the

labels 2023-11-10 08:06:54 +01:00

Philipp Oeser commented

2023-11-10 09:27:23 +01:00

Member

Can confirm, looks like sculpt normals are wrong in this case, will check...

Can confirm, looks like sculpt normals are wrong in this case, will check...

Philipp Oeser added

Sculpt, Paint & Texture

and removed

labels 2023-11-10 09:27:38 +01:00

Philipp Oeser commented

2023-11-10 10:58:39 +01:00

Member

Bisecting...

Bisecting...

Philipp Oeser added

and removed

labels 2023-11-10 10:58:52 +01:00

Philipp Oeser commented

2023-11-10 11:04:41 +01:00

Member

Other modifiers also affected:

Smooth by Angle
UVWarp
VertexWeightEdit
VertexWeightMix

Other modifiers also affected: - `Smooth by Angle` - `UVWarp` - `VertexWeightEdit` - `VertexWeightMix`

Philipp Oeser commented

2023-11-10 11:24:54 +01:00

Member

Caused by 5af8b839cf

CC @HooglyBoogly

Caused by 5af8b839cfc6e3e93869ab6371f2f3c94d35136f CC @HooglyBoogly

Philipp Oeser added the

label 2023-11-10 11:41:25 +01:00

Philipp Oeser changed title from ~~UV Project modifier affects sculpting brushes Clay strip and Scrape~~ to Some modifiers affect sculpting brushes Clay strip and Scrape (normals not updating)

2023-11-10 11:42:03 +01:00

Philipp Oeser changed title from ~~Some modifiers affect sculpting brushes Clay strip and Scrape (normals not updating)~~ to Some modifiers affect sculpting brushes (normals not updating)

2023-11-10 11:42:57 +01:00

Philipp Oeser commented

2023-11-10 13:50:36 +01:00

Member

Problem is that modifiers of type eModifierTypeType_NonGeometrical will still result in the PBVH being considered pbvh->deformed

So stuff like the following is actually true if only such modifiers are present 8which is quite confusing in my opinion)

check_sculpt_object_deformed
sculpt->deform_modifiers_active
BKE_pbvh_is_deformed

Havent dug deeper, but code form 5af8b839cf takes another route for pbvh->deformed than prior (rightfully so), it is just wrong assumptions of what "deformed" can mean.

We could do something like

diff --git a/source/blender/blenkernel/intern/paint.cc b/source/blender/blenkernel/intern/paint.cc
index 4f0f2987419..11d7a39c5d9 100644
--- a/source/blender/blenkernel/intern/paint.cc
+++ b/source/blender/blenkernel/intern/paint.cc
@@ -1628,6 +1628,10 @@ static bool sculpt_modifiers_active(Scene *scene, Sculpt *sd, Object *ob)
       continue;
     }
 
+    if (mti->type == eModifierTypeType_NonGeometrical) {
+      continue;
+    }
+
     if (mti->type == eModifierTypeType_OnlyDeform) {
       return true;
     }

But that in turn results in those modifiers actually being ignored for drawing in sculptmode (BKE_sculptsession_use_pbvh_draw)...

Looks like this could be a bit untangled, not sure wht the short-term solution might be.

Problem is that modifiers of type `eModifierTypeType_NonGeometrical` will still result in the PBVH being considered `pbvh->deformed` So stuff like the following is actually true if only such modifiers are present 8which is quite confusing in my opinion) - `check_sculpt_object_deformed` - `sculpt->deform_modifiers_active` - `BKE_pbvh_is_deformed` Havent dug deeper, but code form 5af8b839cfc6e3e93869ab6371f2f3c94d35136f takes another route for `pbvh->deformed` than prior (rightfully so), it is just wrong assumptions of what "deformed" can mean. We could do something like ```Diff diff --git a/source/blender/blenkernel/intern/paint.cc b/source/blender/blenkernel/intern/paint.cc index 4f0f2987419..11d7a39c5d9 100644 --- a/source/blender/blenkernel/intern/paint.cc +++ b/source/blender/blenkernel/intern/paint.cc @@ -1628,6 +1628,10 @@ static bool sculpt_modifiers_active(Scene *scene, Sculpt *sd, Object *ob) continue; } + if (mti->type == eModifierTypeType_NonGeometrical) { + continue; + } + if (mti->type == eModifierTypeType_OnlyDeform) { return true; } ``` But that in turn results in those modifiers actually being ignored for drawing in sculptmode (`BKE_sculptsession_use_pbvh_draw`)... Looks like this could be a bit untangled, not sure wht the short-term solution might be.

Hans Goudey commented

2023-11-10 15:35:20 +01:00

Member

Thanks for the investigation! I think the core of the issue is that sculpt code expects that deform modifiers actually change positions (causing a normals recalculation), but these modifiers don't. If I put BKE_mesh_tag_positions_changed in the UV project modifier, that fixes the issue.

Indeed this is pretty much a huge mess. Though it isn't a massive issue since it just affects drawing in sculpt mode.
It's probably better to detect differences in the pointers of the custom data layers between the original and evaluated object. That can tell for sure if PBVH drawing should be used.

If it helps to guide us to the right solution, the goal should be sculpting on the original positions of these objects, without allocating separate arrays in the PBVH for normals and positions.

Thanks for the investigation! I think the core of the issue is that sculpt code expects that deform modifiers actually change positions (causing a normals recalculation), but these modifiers don't. If I put `BKE_mesh_tag_positions_changed` in the UV project modifier, that fixes the issue. Indeed this is pretty much a huge mess. Though it isn't a massive issue since it just affects drawing in sculpt mode. It's probably better to detect differences in the pointers of the custom data layers between the original and evaluated object. That can tell for sure if PBVH drawing should be used. If it helps to guide us to the right solution, the goal should be sculpting on the original positions of these objects, without allocating separate arrays in the PBVH for normals and positions.

Pratik Borhade added this to the 4.0 milestone 2023-11-14 07:02:45 +01:00

Philipp Oeser commented

2024-01-04 11:11:56 +01:00

Member

#115433 tells us that Geometry Nodes modifiers are also affected

#115433 tells us that Geometry Nodes modifiers are also affected

Philipp Oeser referenced this issue

2024-01-04 11:19:30 +01:00

Regression: Shader Normals not updating #115433

Pratik Borhade removed this from the 4.0 milestone 2024-01-11 06:55:21 +01:00

Sergey Sharybin commented

2024-01-11 15:49:20 +01:00

Owner

@HooglyBoogly It is not very fair to consider this not a massive issue. Wrong display in sculpt mode is a serious issue for people doing sculpting. While underlying code can be a mess, it is not a reason to ignore huge user level regression.

@HooglyBoogly It is not very fair to consider this not a massive issue. Wrong display in sculpt mode is a serious issue for people doing sculpting. While underlying code can be a mess, it is not a reason to ignore huge user level regression.

Sergey Sharybin self-assigned this 2024-01-11 16:06:50 +01:00

Sergey Sharybin referenced a pull request that will close this issue

2024-01-11 16:09:19 +01:00

Fix #114692: Sculpt on certain modifiers does not update normals #117033

Sergey Sharybin referenced this issue from a commit

2024-01-11 16:15:45 +01:00

Fix #114692: Sculpt on certain modifiers does not update normals

Sergey Sharybin closed this issue

2024-01-11 16:15:46 +01:00

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Hans Goudey added

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labels 2024-01-11 16:51:38 +01:00

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