Help resolving “Multiple bodies with material assignments” error in single region simulation

Using SimScale
1

Hi SimScale Community,

I’m running a single region simulation and encountering the following error:

“Multiple bodies with material assignments were detected. Because this is a single region simulation, only a single body may be assigned a material. Please review your material assignments and leave only the flow volume with a material.”

I’ve double-checked my setup and noticed that multiple solids are listed—possibly all have materials assigned by default. I’m trying to simulate airflow and thermal conditions in an interior architectural space, and I need guidance on:

  1. How to correctly assign material only to the flow region.
  2. Whether non-flow solids (like walls, furniture, etc.) should remain unassigned or be handled differently.
  3. Best practices for managing complex geometry in single region simulations.

Thanks in advance for any insights or suggestions!

2

Hello,

In a single region simulation, only fluid property can be assigned. Please see attached.
You would need to delete the other solid parts as in the tutorial examples.

image
image755×227 6.67 KB

Regards,
Ranjeeth

3

Hey @danagood ,

In addition to @rrnaik_cfd 's comments, if you would like to consider thermal effects from the rest of the solids in your CAD like power sources, then you need to use the Conjugate Heat Transfer simulation. You can find some tutorials here:

If you are only interested in the flow simulation (single flow region), simply delete all the other solids in CAD Edit mode. You can see an example here.

Best,
Satvik