Extract volume
 

I’m new in Star-CCM+, I did a CAD and I imported it in the star-CCM+, it is a complicated geometry with a lot of cavities in irregular shapes how can I extract/subtract volume, I want to add fluid through these cavities but I don’t know what is the best way? Do I need to add a domain or there is another way?.

A similar shape to mine is attached.
Thank you

Can you show/explain a little bit more?

Most operations you can do on the surface level. Remeshing with protection of the geometry (feature lines!) supports you.

My problem is somehow similar to the picture attached. I have the solid but I'm facing a problem how can I add the fluid?

Thank for your replay

If you have the solid body of that geometry then you just need to make a volume which encompasses it and do a boolean subtract.

Considering the complexity of that body I suggest doing this in a CAD package instead of STAR-CCM+.

I think to add a body around is possible with CCM to become a negative.
But I also think direct in CAD is faster.

There are multiple ways to get the fluid volume. You can get it via subtraction in the original CAD package, as others have already mentioned. You can also do the same subtraction in STAR-CCM+, either at the CAD level (3D CAD) or using operations in the parts branch of the tree. This last method support CAD and surface level boolean operations. Lastly, you can use the Extract Volume operation in the parts branch to get the volume.

If your lettice does not contactact any other wall in your domain, you can simply make a box and combine it with your part, no extraction necessary. Then mesh this new part.

Thank you all for your help.

Sorry for this question what is the CAD package is it different from the 3-D CAD thank you.

"the CAD package" is whatever CAD software you are using (Catia, NX, Solidworks, etc). 3D-CAD is STAR-CCM+'s internal CAD software. It is pretty good for a CFD code, but it will struggle with anything really big or complex.