SimScale CAE Forum

CAD model meshing error

Hi every one. I modeled a sphere using Solid Edge. But when I was trying to mesh it I got a message that illegal triangles were found and there is a problem with the CAD geometry. what would be the problem?

Hello @DVV

I took a look to your imported geometry and looks like it has some very small surfaces or textures at the revolution axis ends, try to export from the CAD to another accepted extension file or take a look to the sphere in the Solid Edge to see if this geometry is there.

Here are some resources too about cleaning up in the CAD before exporting to Simscale: CAD Preparation

Hope this helps you.


Yep - great resources to share @mlarreta!

@DVV I think in this case the ‘illegal triangles’ error is misleading, based on the solver log your mesh finished without any errors so you can proceed.

1 Like

Hello @DVV,

I also had a look at your model. As @AnnaFless mentioned your mesh is ok, the message in the Event log is only a warning that is related to a pre-step of the meshing.
The hexahedral meshing is not based on so called rich geometry formats as for example *.step or *.iges, but on triangulated geometries like e.g. *.stl. In general you should not care about this at all as the triangulation is done automatically prior to the meshing. In some cases, if the geometry model is not “clean”, the triangulation can not be done properly and there might be small cracks or duplicated triangles. The meshing is in general very robust in regards to those defects. That is why your mesh is still valid, but we expose this as a warning as it might help in cases where the mesh result does not look as expected.
I checked on your geometry model and it seems to be a clean sphere. Thanks @mlarreta for looking into the issue. I can also see those very small, irregular surfaces. It seems to be a visualization problem though. The geometry model should be fine. I reported both issues, the visualization problem and the irregular triangles, as of course for a valid sphere model the triangulation should not have any problems!

Thanks for reporting this! Helps a lot!

Best Alex