Quad remesher produces exotic self-intersecting mesh despite apparently simple source mesh #90310

New Issue

George Hawkins · 2021-07-29T20:37:15+02:00

George Hawkins commented

2021-07-29 20:37:15 +02:00

System Information
Operating system: Ubuntu 20.04.1 LTS
Graphics card: RTX 2060

Blender Version
Broken: 2.93.1
Worked:

Short description of error

Despite an apparently simple source mesh (manifold and normal conditions are met and mesh is not self-intersecting), Quad remesh produces an exotic self-intersecting mesh where an area of faces flow together to form a point that pierces through the resulting mesh.

Exact steps for others to reproduce the error

Meshroom produces meshes with a huge number of vertices that I then clean up in Blender - the final step being to remesh with the*Quad// remesher.

However, the results often contain unexpected issues - in particular instead of nice clean quads, there are often points where the quads flow together into a point that then pierces through the mesh.

E.g. here we can see quads flowing together on the right and then piercing through the mesh on the left:

The corresponding area of the original mesh doesn't seem to have any obvious issues:

I often encounter similar issues with meshes that I work on - despite having applied serious effort to cleaning up the meshes (using the Mesh / Clean Up functionality, a lot of manual cleanup and breaking up any intersecting faces in the original mesh with Face / Intersect (Knife) with the Self Intersect option).

I've attached a 6MB .blend file that contains the cleaned-up original mesh as "low-poly" and the remeshed version as "low-poly-remesh":

bust-low-poly-bug-report.blend

The original object looks like this:

After remeshing the problem shown up above can be seen on the right:

I've also highlighted on the left a weird spike that doesn't appear to correspond to anything in the original mesh but that's probably something for a separate bug report.

The remeshed object was created by duplicating "low-poly", renaming it "low-poly-remesh", going to Object Data Properties, expanding Remesh, selecting Quad and setting 40000 as the Number of Faces value.

I left all the other settings, i.e. Use Mesh Symmetry etc., as they were (but separate experiments with them produced different but still problematic results).

**System Information** Operating system: Ubuntu 20.04.1 LTS Graphics card: RTX 2060 **Blender Version** Broken: 2.93.1 Worked: **Short description of error** Despite an apparently simple source mesh (manifold and normal conditions are met and mesh is not self-intersecting), *Quad* remesh produces an exotic self-intersecting mesh where an area of faces flow together to form a point that pierces through the resulting mesh. **Exact steps for others to reproduce the error** [Meshroom](https:*alicevision.org/) produces meshes with a huge number of vertices that I then clean up in Blender - the final step being to remesh with the*Quad// remesher. However, the results often contain unexpected issues - in particular instead of nice clean quads, there are often points where the quads flow together into a point that then pierces through the mesh. E.g. here we can see quads flowing together on the right and then piercing through the mesh on the left: ![image.png](https://archive.blender.org/developer/F10245490/image.png) ![image.png](https://archive.blender.org/developer/F10245496/image.png) The corresponding area of the original mesh doesn't seem to have any obvious issues: ![image.png](https://archive.blender.org/developer/F10245494/image.png) I often encounter similar issues with meshes that I work on - despite having applied serious effort to cleaning up the meshes (using the *Mesh / Clean Up* functionality, a lot of manual cleanup and breaking up any intersecting faces in the original mesh with *Face / Intersect (Knife)* with the *Self Intersect* option). I've attached a 6MB `.blend` file that contains the cleaned-up original mesh as "low-poly" and the remeshed version as "low-poly-remesh": [bust-low-poly-bug-report.blend](https://archive.blender.org/developer/F10245516/bust-low-poly-bug-report.blend) The original object looks like this: ![image.png](https://archive.blender.org/developer/F10245517/image.png) After remeshing the problem shown up above can be seen on the right: ![image.png](https://archive.blender.org/developer/F10245521/image.png) I've also highlighted on the left a weird spike that doesn't appear to correspond to anything in the original mesh but that's probably something for a separate bug report. The remeshed object was created by duplicating "low-poly", renaming it "low-poly-remesh", going to *Object Data Properties*, expanding *Remesh*, selecting *Quad* and setting 40000 as the *Number of Faces* value. I left all the other settings, i.e. *Use Mesh Symmetry* etc., as they were (but separate experiments with them produced different but still problematic results).

George Hawkins commented

2021-07-29 20:37:15 +02:00

Added subscriber: @GeorgeHawkins

Richard Antalik commented

2021-08-05 05:43:10 +02:00

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

Philipp Oeser removed the

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

Quad remesher produces exotic self-intersecting mesh despite apparently simple source mesh #90310