QuadriFlow with the new symmetry option creates holes at the center #70342

New Issue

Frozen_Death_Knight · 2019-09-29T04:29:12+02:00

2019-09-29 04:29:12 +02:00

System Information
Operating system: Windows-10-10.0.18362 64 Bits
Graphics card: GeForce GTX 980/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 436.30

Blender Version
Broken: version: 2.81 (sub 12), branch: master (modified), commit date: 2019-09-27 17:16, hash: be985bdde2

Short description of error
QuadriFlow creates hole artifacts like these when remeshing. Usually occurs after using Voxel Remesher and/or Dyntopo which can break symmetry at the center very often.

Exact steps for others to reproduce the error

Sculpt something in Sculpt Mode and use Voxel Remesher/Dyntopo.
Start QuadriFlow. It doesn't always produce these holes in the mesh, but keep repeating part one and two and you will eventually get these holes where each side hasn't been properly merged together.

**System Information** Operating system: Windows-10-10.0.18362 64 Bits Graphics card: GeForce GTX 980/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 436.30 **Blender Version** Broken: version: 2.81 (sub 12), branch: master (modified), commit date: 2019-09-27 17:16, hash: `be985bdde2` **Short description of error** QuadriFlow creates hole artifacts like these when remeshing. Usually occurs after using Voxel Remesher and/or Dyntopo which can break symmetry at the center very often. ![Openings in the symmetrical QuadriFlow.png](https://archive.blender.org/developer/F7779163/Openings_in_the_symmetrical_QuadriFlow.png) **Exact steps for others to reproduce the error** 1) Sculpt something in Sculpt Mode and use Voxel Remesher/Dyntopo. 2) Start QuadriFlow. It doesn't always produce these holes in the mesh, but keep repeating part one and two and you will eventually get these holes where each side hasn't been properly merged together.

Frozen_Death_Knight commented

2019-09-29 04:29:12 +02:00

Added subscriber: @Frozen_Death_Knight

blender-admin commented

2019-09-29 04:29:12 +02:00

#72694 was marked as duplicate of this issue

Brecht Van Lommel commented

2019-09-29 13:43:14 +02:00

Added subscriber: @brecht

Brecht Van Lommel commented

2019-09-29 13:43:14 +02:00

We require an example .blend file.

Pablo Dobarro self-assigned this 2019-09-29 13:43:42 +02:00

Frozen_Death_Knight commented

2019-09-29 14:03:19 +02:00

@brecht Do you require a mesh that hasn't been remeshed with QuadriFlow or a sculpt that has? I can provide both if you like.

Frozen_Death_Knight commented

2019-09-29 14:31:32 +02:00

Before and After QuadriFlow.blend

Here's how it looks like before and after:

You can try to remesh the "Before" model and see the results yourselves.

Also, I would like to report that QuadriFlow is still very unstable. Even when using the default settings with a ratio of 1.00 and Use Paint Symmetry on, using this remesher very often crashes Blender. It also fails very often when trying to remesh somewhat high density meshes like 100k polys (trying to match the density with a 1.000 ratio will often fail on meshes). It often gets stuck at 50% and never finishes or just simply crashes or fails to remesh.

Plus, seeding can also very often lead to Blender crashes.

[Before and After QuadriFlow.blend](https://archive.blender.org/developer/F7779668/Before_and_After_QuadriFlow.blend) Here's how it looks like before and after: ![Before and After QuadriFlow.png](https://archive.blender.org/developer/F7779669/Before_and_After_QuadriFlow.png) You can try to remesh the "Before" model and see the results yourselves. Also, I would like to report that QuadriFlow is still very unstable. Even when using the default settings with a ratio of 1.00 and Use Paint Symmetry on, using this remesher very often crashes Blender. It also fails very often when trying to remesh somewhat high density meshes like 100k polys (trying to match the density with a 1.000 ratio will often fail on meshes). It often gets stuck at 50% and never finishes or just simply crashes or fails to remesh. Plus, seeding can also very often lead to Blender crashes.

Brecht Van Lommel commented

2019-09-29 14:34:51 +02:00

We need exact steps to reproduce problems, which in this case means a .blend file where we can run quadriflow remesh, and it gives wrong results or crashes.

Frozen_Death_Knight commented

2019-09-29 14:37:34 +02:00

@brecht I just provided one. The object named "After" is the results I get when remeshing with QuadriFlow using just the basic settings. Hopefully you get the same results I got when doing the same on the "Before" object. You can keep remeshing with QuadriFlow if it doesn't crash for you the first time. It eventually does that every time on my end.

Enrique Barranco commented

2019-11-21 08:25:40 +01:00

Added subscriber: @ebarranco

Pablo Dobarro was unassigned by Dalai Felinto

2019-12-23 13:48:57 +01:00

Dalai Felinto commented

2019-12-23 13:48:57 +01:00

Added subscriber: @PabloDobarro

Pablo Dobarro commented

2019-12-24 01:02:53 +01:00

This is produced by the way Quadriflow remesh produces symmetry. It mirrors the mesh and welds the vertices, so it is not possible to find a fixed threshold that fits all mesh results and scales. Furthermore, the preserver mesh boundary option that is needed to snap the vertices to the symmetry edge is not 100% reliable. We can do some mesh post processing to snap the vertices to the symmetry plane, but it is also not going to work for all cases (see D5938). Symmetry needs to be supported directly in Quadriflow to avoid these kind of issues.

This is produced by the way Quadriflow remesh produces symmetry. It mirrors the mesh and welds the vertices, so it is not possible to find a fixed threshold that fits all mesh results and scales. Furthermore, the preserver mesh boundary option that is needed to snap the vertices to the symmetry edge is not 100% reliable. We can do some mesh post processing to snap the vertices to the symmetry plane, but it is also not going to work for all cases (see [D5938](https://archive.blender.org/developer/D5938)). Symmetry needs to be supported directly in Quadriflow to avoid these kind of issues.

Pablo Dobarro commented

2019-12-26 23:35:55 +01:00

Added subscribers: @PaulGeraskin, @DanielBystedt

paul geraskin commented

2019-12-29 16:24:24 +01:00

Hello.
This is just to remind about the artifacts.
https://developer.blender.org/T72694
Thanks!

Hello. This is just to remind about the artifacts. https://developer.blender.org/T72694 Thanks! ![image.png](https://archive.blender.org/developer/F8244862/image.png)

s12a commented

2022-06-13 10:54:29 +02:00

Added subscriber: @s12a

Philipp Oeser removed the

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QuadriFlow with the new symmetry option creates holes at the center #70342