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Missing triangles/holes in surface mesh (fixed, update to 1.0.4a) #372
Blender Version (including hash):
Describe the bug
I do see a lot of holes, missing polygons (non-manifold geometry) that I didn't notice in earlier versions?
Imported geometry (Alembic), made a domain and fluid in Blender, tried the Coffee preset for settings!
No missing polygons!
some missing polygons in the fluid mesh, see screenshots!
Yes of course! I uploaded them and shared them from my dropbox, the .zip also includes all the files including the Cache if needed! I hope that works?
Just giving an update on this issue. The problem that is causing the holes in the fluid mesh has been found and a solution for how to fix this is understood. However, while investigating this issue we have identified some other problems within the new particle mesher that are also causing chunks of the mesh to be incomplete.
Non-manifold parts within the fluid mesh is quite a serious issue as this has consequences in rendering. Our priority at the moment is fixing all issues within the particle mesher. We will be releasing a patched version (1.0.4a) as soon as we can fix these problems and test the updates. Hopefully within one week.
The issues are related to the domain size (and world scaling) and also number of mesh subdivisions. Using small domains or small world scales in combination with higher mesh subdivisions (1 and 2) may increase the frequency of missing polygons. A workaround that may help is using domain sizes/scales larger than 5 metres wide and limiting number of subdivisions to a maximum of 1.
If a reliable mesher is needed, I would have to suggest reverting back to version 1.0.3 until these issues are fixed. Sorry for the inconvenience and thank you for your patience!
changed the title from
Holes in fluidmesh, missing polygons
Holes and missing triangles/parts of fluid surface mesh
Aug 23, 2018
This issue has been fixed and will be included in a patched version v1.0.4a that will be available August 24th, 2018. It is highly advised to upgrade to the patched version as this update will fix some major bugs within the particle mesher (#376, #377).
This bug was caused by numerical precision errors. The mesher calculates the surface mesh in chunks and then 'welds' the pieces together to join the vertices/edges. When triangles become small, there can be numerical errors in CPU calculations due to the finite amount of precision that a 32-bit number stores. These precision errors caused vertices not to line up properly and they would not become 'welded' together resulting in holes within the surface mesh. This issue has been fixed by internally scaling the mesh to an appropriate size so that the CPU can handle calculations accurately while joining mesh chunks.