Multi-region mesh problem

this is my first project i tried to simulate. But even though I tried different setups, I always got this error:

“A multi-region mesh was assigned - this analysis-type requires a single-region mesh.”

Can anyone please help me

Working on creating a post to finally cover that either in the documentation or FAQs.



Hi @ja_ba_bu: You can help yourself. For that kind of internal simulation you need just one solid. Currently you have 4 solids.

If in your CAD software you make a boolean ‘union’, you should get just one solid. Importing it to SimScale will open the door to correct meshing and simulation.

Another way would be to click on your geometry in SimScale and select ‘Add geometry operation’. You should merge your four solids into one, becoming a simulation domain (just the water inside your device).

Take care,



Thank you very much!!

Hello, I have same issue. but we cant just have 1 solid when using MRF Rotation zone right? I have follow video tutorial but still can’t figure it out. please help


For simulations with MRF rotating zones, you need 2 volumes in your geometry:

  • Flow region
  • Rotating zone

Note that solid parts (such as the actual solid blades) should not be in the geometry. You will only capture the negative volume of the blades in the flow region volume.

Make sure to check these 2 articles about this topic:


Thank you so much, it’s help