Weld Modifier Improvements #73139

New Issue

Germano Cavalcante · 2020-01-15T15:43:46+01:00

2020-01-15 15:43:46 +01:00

Motivation

Although the current state of the weld modifier already solves almost all cases,
it is always good to have more options that allow for better control over mesh transformations and better performance control.

Proposal

Seams: restrict welding to vertices along boundary edges.
Edge Collapse: collapse edges below the length threshold.
Duplicate Limit: work on groups of vertices (as is done in Decimate) and not on a chain of elements that have a minimum distance in common.

There will be two methods available:

Simple (default)

This would be a fast weld operation that would support common welding operations - weld-seams/collapse-edges
although other cases could be supported in the future.

Merging geometry that would cause degenerate faces will be skipped
(this requires much more complex operation to properly handle).

Full

Current implementation that perform a full merge-by-distance,
with support for resolving degenerate cases, documented to be much slower
then the Simple operation.

Pros

Fast by default, for merging boundaries of disconnected surfaces.
The ability only to merge a small subset of vertices should speed up the operation in most real world uses.

Cons

The Full merge-by-distance code uses a method that depends on vertex order

(picking all vertices closest to vertices at the start of the mesh). This means changing the vertex order of the input may cause the result
to *jitter*.

The Simple method will have limitations which might be hard to understand. Ideally we wouldn't have to select between two methods.

Other ToDos

New icon for the modifier.
Some customdata types are not being correctly interpolated (vertex weight).
Cache BVHTree.

Obs.: The two rows for modifier icons are already filled. We need to think of a way to organize the new icon.

**Motivation** Although the current state of the weld modifier already solves almost all cases, it is always good to have more options that allow for better control over mesh transformations and better performance control. **Proposal** - Seams: restrict welding to vertices along boundary edges. - Edge Collapse: collapse edges below the length threshold. - Duplicate Limit: work on groups of vertices (as is done in Decimate) and not on a chain of elements that have a minimum distance in common. There will be two methods available: - **Simple** (default) ``` This would be a fast weld operation that would support common welding operations - weld-seams/collapse-edges although other cases could be supported in the future. ``` ``` Merging geometry that would cause degenerate faces will be skipped (this requires much more complex operation to properly handle). ``` - **Full** ``` Current implementation that perform a full merge-by-distance, with support for resolving degenerate cases, documented to be much slower then the Simple operation. ``` ---- **Pros** - Fast by default, for merging boundaries of disconnected surfaces. - The ability only to merge a small subset of vertices should speed up the operation in most real world uses. **Cons** - The **Full** merge-by-distance code uses a method that depends on vertex order ``` (picking all vertices closest to vertices at the start of the mesh). This means changing the vertex order of the input may cause the result to *jitter*. ``` - The **Simple** method will have limitations which might be hard to understand. Ideally we wouldn't have to select between two methods. ---- **Other ToDos** - New icon for the modifier. - Some customdata types are not being correctly interpolated (vertex weight). - Cache BVHTree. Obs.: The two rows for modifier icons are already filled. We need to think of a way to organize the new icon. ![image.png](https://archive.blender.org/developer/F8207678/image.png)

Germano Cavalcante commented

2020-01-15 15:43:46 +01:00

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

Germano Cavalcante commented

2020-01-15 15:43:46 +01:00

Added subscribers: @mano-wii, @ideasman42

Oliver Milas commented

2020-01-15 15:54:03 +01:00

Added subscriber: @Spatz

Henrik D. commented

2020-09-17 18:40:31 +02:00

Added subscriber: @HDMaster84

Henrik D. commented

2020-09-17 18:40:32 +02:00

I am looking forward to the Simple Mode. Currently your Simple Mode is kind of implemented in complex solidify,
but due to #80897 I started thinking about removing it. Also adding a good fallback value in the spot in the code where no
zero edges are allowed.

Make sure to put checkboxes for the seams and the inside edges, so they can be used individually to match the behavior.
Simple Mode is really important to keep the mesh manifold even when it is self-intersecting (take cloth as an example).

Also a sneaky feature request here:
I would like a keep islands separate option for the full weld, so it will not merge geometry which is completly disconnected.

I am looking forward to the **Simple Mode**. Currently your Simple Mode is kind of implemented in complex solidify, but due to #80897 I started thinking about removing it. Also adding a good fallback value in the spot in the code where no zero edges are allowed. Make sure to put checkboxes for the seams and the inside edges, so they can be used individually to match the behavior. Simple Mode is really important to keep the mesh manifold even when it is self-intersecting (take cloth as an example). Also a sneaky feature request here: I would like a keep islands separate option for the full weld, so it will not merge geometry which is completly disconnected.

Philipp Oeser removed the

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Weld Modifier Improvements #73139