Sub-D Workflow in Grasshopper – Bridging Meshes

Hello there,

at the moment i am experimenting modeling with sub-d and grasshopper.
I am constructing meshes inside grasshopper by lofting, railing etc. and later converting them to sub-d.

Now I want to connect the different meshes together at specific areas.
I want to bridge i.e. two adjacent mesh faces with two on another mesh.
My thought process is to loft between the outer edges of the respective adjacent mesh edges. But I don’t find a way to get the outer boundaries of the merged adjacent mesh faces.

The faces i want to bridge

The result i try to achieve in GH

Has anyone already figured out such a sub-d workflow by constructing meshes or has any idea of how to achieve the result?

PS: I have already tried the Mesh+ ‘Bridge and Span’ component, but it does only seem to work for connecting single faces. (19.9 KB)

Wow, thank you for this fast and thorough answer, thats already much more than i expected!

@DanielPiker that’s nice. I notice interesting things happen when the point is right in the middle of vertices:


As a quick way of selecting the faces to bridge I made it pick the closest n faces to the ends of the line (with n set to 4 in the example). When the end is close to a mesh vertex this results in a square patch, but as you found, when it is in the middle of a face, it results in a T shaped patch.

You could also use other ways of selecting the faces, such as containment within some solid.

If the patches selected don’t have an equal number of edges on their borders it will give odd results.

On a related note - one thing I’ve made as part of the ‘Fuse’ command I’m working on is a sort of bridge that works even in cases where the edge loops to be bridged don’t have matching numbers of edges
(it’s not always possible to make the bridge with all quads if the sum of the loop edge counts is not an even number, so this will sometimes contain a few triangles, but since these each get refined to 3 quads at the first subdivision step, that isn’t necessarily a problem).