How can we join an open polysurface to a closed polysurface to make it a single unit?
boolean union removes the closed polysurface after execution and join does not work.
example shown below (in attd. images)
Hi @karishma
Technically yes, you can. But you probably don’t want to…
You can use NonmanifoldMerge to merge them together, but unless you have a really specific reason to do so, you are much better off using Group, as nonmanifold geometries will give you all kinds of headaches downstream.
HTH, Jakob
hi @Normand
thanks for the solution provided. i tried and thankfully its working. however, i had a concern as you said “yes you can but you probably don’t want to” so, i just wanted to know, are non manifold polysurfaces bad and do they affect the analysis process?
Hi @karishma
Non-manifolds can lead to problems with booleans, splits, export to some formats and probably a lot of other geometry-based operations later on. Non-manifold objects are generally considered “bad” in NURBS, so unless you have a specific reason for them, you should rather a) give thickness to the upper edge, so that you can use BooleanUnion to join them together, or b) Use Group for a more temporary solution. But again, it all depends on what you need it for. I’m sure there are cases, where non-manifolsd are just fine 
-Jakob
@Normand
okay
thanks!