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

Convective heat transfer.

I asked my friend to build a model of a shopping mall in Revit, then I convert it into AutoCAD and use the command"union" to make all the parts into one.
But when I start simulation run after meshing, the error pops
A multi-region mesh was assigned - this analysis-type requires a single-region mesh. Learn more.
which is page not found

But I don’t want to rebuild it in autocad coz it is very time consuming

Hi there!

Can you please share the URL to your project so we can have a look and find the solution to the error?

By the error message, I can see that you have a CAD with multiple parts. In a Convective Heat Transfer analysis, the fluid region must be the only volume in the body.

Please also describe your project and what you need to achieve with the simulation, this way we can offer better support.



This is a 4-floor space, kind of a shopping mall atrium. with 20-30 air inlets at each floor at 1 return(pressure outlet), on the first floor, there are some jet diffuser designed for the big void at the center of the atrium

I appreciate everyone that spend time on this, my intention is to replicate something similar to https://www.youtube.com/watch?v=Y4Ja_JtuIdg&ab_channel=SimScaleGmbH

Hi again!

Thanks for the link to the project, I was able to have a look, and found this:

You currently have solid model for the walls and ducts, but for the simulation, you must have an only volume corresponding to the region filled with air.

You can easily create this volume from your current model by performing a Flow volume extraction - closed inner region. You can find instructions in this page:

So you are saying I need to rebuild the model because the wall is a 3d solid, and revit is not the correct tool to build the model I needed

I am sorry, maybe the explanation wasn’t clear enough? Did you read the linked page?

You don’t need to rebuild the model, you need to create the Flow Volume Extraction (as explained in the linked doc page)