Knife Tool / Knife Project: Vertex group weights not added/interpolated for KnifeVerts created in faces (works correctly on verts created on existing/split edges) #50604

New Issue

Serge Lyatin · 2017-02-06T15:01:13+01:00

Serge Lyatin commented

2017-02-06 15:01:13 +01:00

System Information
Win7 32bit

Blender Version
Broken: 3.4
Broken: 2.78

Short description of error
Knife Tool / Knife Project: Vertex group weights not added/interpolated for KnifeVerts created in faces (works correctly on verts created on existing/split edges)

Exact steps for others to reproduce the error

create a plane
subdivide once
add a vertexgroup (all vertices with 1.0 weight)
use the knife tool (or Knife Project operator)
notice where existing edges are split, vertex weights are added/interpolated to new verts on that edge
newly created verts inside faces are not added to vertex groups though
#50604.webm

Original Report
Last cutting was done by simple Knife to show the difference
0001-0324.mp4

In .Blend hit Knife project
Knife_project.blend

**System Information** Win7 32bit **Blender Version** Broken: 3.4 Broken: 2.78 **Short description of error** Knife Tool / Knife Project: Vertex group weights not added/interpolated for KnifeVerts created in faces (works correctly on verts created on existing/split edges) **Exact steps for others to reproduce the error** - create a plane - subdivide once - add a vertexgroup (all vertices with 1.0 weight) - use the knife tool (or Knife Project operator) - notice where existing edges are split, vertex weights are added/interpolated to new verts on that edge - newly created verts inside faces are not added to vertex groups though [#50604.webm](https://archive.blender.org/developer/F13411108/T50604.webm) **Original Report** Last cutting was done by simple Knife to show the difference [0001-0324.mp4](https://archive.blender.org/developer/F447026/0001-0324.mp4) In .Blend hit *Knife project* [Knife_project.blend](https://archive.blender.org/developer/F447078/Knife_project.blend)

Serge Lyatin commented

2017-02-06 15:01:13 +01:00

Changed status to: 'Open'

Serge Lyatin commented

2017-02-06 15:01:13 +01:00

Added subscriber: @SergeL

blender-admin commented

2017-02-06 15:01:13 +01:00

#100554 was marked as duplicate of this issue

Bastien Montagne commented

2017-02-06 15:21:20 +01:00

Added subscriber: @mont29

Bastien Montagne commented

2017-02-06 15:21:21 +01:00

Am tired of repeating this a bit:

*Please follow our submission template and guidelines and make a complete, valid bug report, with required info, precise description of the issue, precise steps to reproduce it, small and simple .blend and/or other files to do so if needed, etc.
Videos and/or links to external sites etc. are not acceptable as bug report (they can be provided as additional information only).
//

Am tired of repeating this a bit: ***Please follow our [submission template and guidelines](https:*developer.blender.org/maniphest/task/edit/form/1/) and make a complete, valid bug report, with required info, precise description of the issue, precise steps to reproduce it, **small and simple** .blend and/or other files to do so if needed, etc. Videos and/or links to external sites etc. **are not acceptable** as bug report (they can be provided as additional information **only**). //**

Serge Lyatin commented

2017-02-06 16:07:47 +01:00

I am sorry.
In .Blend hit Knife project
Knife_project.blend

I am sorry. In .Blend hit *Knife project* [Knife_project.blend](https://archive.blender.org/developer/F447076/Knife_project.blend)

Bastien Montagne commented

2017-02-06 17:39:44 +01:00

Changed status from 'Open' to: 'Archived'

Bastien Montagne closed this issue

2017-02-06 17:39:44 +01:00

Bastien Montagne self-assigned this 2017-02-06 17:39:44 +01:00

Bastien Montagne commented

2017-02-06 17:39:44 +01:00

Hmmm… do not agree here, knife have same behavior as knife project here: it interpolates vgroups when creating vertices on existing edges, not when creating vertices on new edges (you can see that with knife by drag-drawing complex line cutting itself several times, vertices created at intersections of non-yet-existing edges also ignore existing vgroups).

Thanks for the report, but will consider this a TODO, would be nice to interpolate vgroups based on neightbor vertices, but that’s not technically a bug currently imho. Added entry to https://wiki.blender.org/index.php/Dev:Source/Development/Todo/Tools#Mesh_Editing.

Hmmm… do not agree here, knife have same behavior as knife project here: it interpolates vgroups when creating vertices on existing edges, not when creating vertices on new edges (you can see that with knife by drag-drawing complex line cutting itself several times, vertices created at intersections of non-yet-existing edges also ignore existing vgroups). Thanks for the report, but will consider this a TODO, would be nice to interpolate vgroups based on neightbor vertices, but that’s not technically a bug currently imho. Added entry to https://wiki.blender.org/index.php/Dev:Source/Development/Todo/Tools#Mesh_Editing.

Campbell Barton commented

2019-09-03 04:07:23 +02:00

Changed status from 'Archived' to: 'Open'

Campbell Barton reopened this issue

2019-09-03 04:07:23 +02:00

Campbell Barton changed title from ~~Vertex group doesn't add vertices from knife project tool~~ to Vertex group doesn't add vertices from knife tool

2019-09-03 04:07:40 +02:00

Bastien Montagne removed their assignment 2020-01-08 19:51:22 +01:00

Philipp Oeser changed title from ~~Vertex group doesn't add vertices from knife tool~~ to Knife Tool / Knife Project: Vertex group weights not added/interpolated for KnifeVerts crated in faces (works correctly on verts created on existing/split edges)

2022-08-22 14:17:50 +02:00

Philipp Oeser commented

2022-08-22 14:21:11 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2022-08-22 14:21:11 +02:00

I'd like to raise priority on this one (has also been reported again in #100554).

For one, it would be good to define what custom data layers are usually expected to be preserved/interpolated in modeling tools (see also #97698).
For this report though, doing it for certain vertices (but not for all) in a single tool/operator seems very inconsistent.

I'd like to raise priority on this one (has also been reported again in #100554). For one, it would be good to define what custom data layers are usually expected to be preserved/interpolated in modeling tools (see also #97698). For this report though, doing it for certain vertices (but not for all) in a **single tool/operator** seems very inconsistent.

Philipp Oeser commented

2022-08-22 14:22:36 +02:00

Added subscriber: @NB030

Philipp Oeser changed title from ~~Knife Tool / Knife Project: Vertex group weights not added/interpolated for KnifeVerts crated in faces (works correctly on verts created on existing/split edges)~~ to Knife Tool / Knife Project: Vertex group weights not added/interpolated for KnifeVerts created in faces (works correctly on verts created on existing/split edges)

2022-08-22 14:22:54 +02:00

Philipp Oeser removed the

Interest

Modeling

label 2023-02-09 15:30:04 +01:00

Campbell Barton referenced this issue

2024-12-05 05:28:21 +01:00

Modeling: Quality Project (Dec '24 / Jan '25) #131361

Philipp Oeser referenced a pull request that will close this issue

2024-12-06 13:44:40 +01:00

Fix: Knife tool does not interpolate vertex customdata in interior cuts #107367

Philipp Oeser commented