Fillet/Blend on closed polysurfaces

Hello all,
I do understand Rhino is NURBS, not solid modeller, but I want to have an advice because filleting closed polysurfaces is topic I got always serious issues and take huge amount of time to split & blend hundreds of surfaces manually.


Object is closed polysurface, all edges fit without gaps.
This is a constant issue since I work with Rhino.


Hi -

You need to make sure to check the position of every edge and the size of the fillet.
Without a 3dm file, there’s not much more to say about that, I’m afraid.

Dear Wim,
thanks for your reply.

Probably I miss something in the process of filleting/blending surfaces.

Is there an option at least those fillet chain/edges to be saved as closed curve
automatically, to be used later as path for pipe creating? For complex polysurfaces this will be advantage.

File saved small attached. Fillet/blend radius should be 2mm. (2.7 MB)


Without downloading the file, just looking at the pictures:
Your fillets are bigger (or equal) along the borders than some corner fillets they are supposed to follow along.
This makes the theoretical inner radius smaller (or equal to) than zero, which causes Rhino’s filletedge to fail.


Hello- @norbert_geelen is spot on - the radius of the fillet is larger than the radius of the edges that are being filleted - you’ll need to make these transitions by hand and join them in with what Filletedge has given you, or, make those edge radii larger, or add handles locally to make the fillet radius smaller.


1 Like

Thanks so much for your advice!

Thanks! It is important witch edges are selected for filleting/blending also … however I got a lot of things to learn :slight_smile: