Brep property problem

Hi! I am trying to use code to determine if the result of my solid union is manifold/solid (i.e. is watertight, and is considered a ‘body,’ not ‘surface’ when imported to other software)

I see the following properties, which of them should I use? (they seem to be the same thing?)
IsManifold
IsValid
IsSolid

I’m so confused :skull:

Thanks a lot!

I would use all three maybe. IsValid just checks to see if it’s not a bad object for Rhino, but that’s probably a good thing for other software. IsSolid checks to see if it’s closed, which is the most important. Normally that would also imply IsManifold, but it is possible to have two or more disjoint closed volumes that have been merged to make a non-manifold object that might still pass IsSolid.

Thanks for your reply! I see!