I’ve published an update, which includes a few more nodes for solid operations for API solids:
SolidsIntersection:
DoSolidsIntersect - the same but only returns True or False
SolidsUnion:
Also some other handy nodes, such as all 3 coordinates of a point and bulk get StartPoint EndPoint of a Line.
Still working on Dynamo to RevitAPI Solid Conversion. Wasn’t as easy as I thought 
Hi! Thanks for reaching out. Could you please share a sample file with those two elements?
@danail.momchilov, it’s just two simple walls without any inserts. Thanks!
now that’s just extremely weird… managed to recreate the issue and tested it in Revit 21, 23 and 24. However, check this out:
If you intersect the united solids with the original ones, using the same nodes, you actually get a correct result…
Also, intersecting just one of the walls with another element, like a floor for instance, works perfectly…
So that’s a really weird issue indeed so far I’ve used these nodes mainly in order to identify intersections between structural and MEP elements and never had any trouble
In particular, the DoSolidsIntersect node could not be any more simple:
public static bool DoSolidsIntersect(Autodesk.Revit.DB.Solid solidA, Autodesk.Revit.DB.Solid solidB)
{
try
{
Autodesk.Revit.DB.Solid intersection = BooleanOperationsUtils.ExecuteBooleanOperation(solidA, solidB, BooleanOperationsType.Intersect);
if (intersection != null && intersection.Volume != 0)
return true;
else
return false;
}
catch (Exception e)
{
throw e;
}
}
So it seems like it could be some kind of general limitation or a bug within the API itself, but I will have to dig further 
In the meantime, could you please try to test them with some other elements as well?
