Back again with another annoying problem. I’ve been attempting to mesh a large complex urban environment and it has been relatively problem free with the exception of this problem. The project link is here. The mesh basically creates strange deformations as if it is overlaying each other causing the cells to be very skewed and when a simulation is attempted, instability will occur resulting eventually in an error. Below are examples of where these occur, but they do occur everywhere within the geometry.
Normally if I were out of ideas I would re-mesh it while tuning the refinements to get it right but if you look into the project itself it is very costly to always re-mesh such a geometry, hence any help would be much appreciated!
I’ve tried removing the surface refinement at the floor containing the elevated ground where the problematic area is along with increasing surface refinement of the individual buildings but the problem still persists.
Another peculiar problem that might actually be the cause of the issue. As seen in the two figures taken from identical angles, the floor elevation consisting of a sloped gradient has disappeared in the meshing phase.
I have had this issue when both an internal and an external mesh is created on a face. Maybe it would be worth creating a solid geometry to ensure this doesn’t happen, for me the geometry had holes, but if the bounding box doesn’t properly intersect your floor, this might also cause it.
The geometry is open due to the nature of the case but it should work. Good suggestion on making the section giving problems a solid I will try to see if i can do that. Making the geometry entirely solid is another issue all together, any suggestions on how to do so? Do i need to enclose the bottom surface first?
The geometry also has lower floors at the same level or even lower than that of the elevated/sloped floors and it didn’t have problems so it is rather strange.
Yes, what I would do is bring the model into CAD maybe as an STL, convert it to faces, fill the bottom and hopefully it will be enclosed and can, therefore, be converted to a solid. If some of the floors are level with the bottom maybe extend the bottom to ensure that a solid floor is present. If you cannot enclose, you might need to do some CAD cleanup.
I presume you have tried just raising the bottom of the bounding box a bit and meshing?
Thanks for the great input as always. I’m currently attempting to do as you suggested and its meshing at the moment so we’ll see how it goes.
Accuracy is an important factor so I aim to keep the geometry as original as possible since this is a validation case. So no I have not slightly raised the floor bounding box, but that is an excellent suggestion to raise it just enough to see what happens to the mesh. Will attempt it if the previous suggestion dosen’t work.
Edit:
The rough run is done and apparently it seems like the issues are not there anymore! Will re-run this geometry with the full details to see if it actually holds up.
Edit 2:
Simulation does hold up! Thanks Darren for the solutions!
Yup! Used OnShape to do it! The fill function is brilliant and as long as you have a proper clean geometry that is made up of solids (at least at the critical areas) then the meshing process should be relatively painless.
