Solids from surfaces - boundary or join

Hi all, having issues with making a solid out of surfaces and i don’t think this is a GH tolerance issue, as I tried changing the tolerace way way up and nothing changed. I also tried using differnt ways of doing this but still not working. I may be missing something and can’t figure out what. Your help is appreciated. Started in GH a week ago but making lots of progress in undertsanding concepts and making it work for me, just this one is new. Thank you.
See attached.

Rhino.3dm (51.9 KB) Brep Join and Boundary (40.3 KB)

The first option works when i open your files:

for the second are missing a surface here. there should be another face to fully enclose the volume

here’s an example of using bounding volume

Bounding (12.7 KB)
surfaces are internalised

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Thank you for the example of volume boundaries, I like how simplified it is! As for the joining example, you’re right the example i did works, i must have been GH exhausted yesterday. Will try and troubleshoot why it didn’t work int the main project file i’m working in or find a simpler way to do what i’m trying to do. Thanks!

still having a problem with joining BREPs in more complex situations. See example attached and let me know if you know what i’m doing wrong. When i bake the surfaces they are not joined in Rhino, which prevents me from continuing with the project in GH. What puzzles me is that the center surface shares edges with the other two so should be able to join but doesn’t. Thanks. (9.5 KB)


I took a wild guess about where you are going with this? Surprised to see a “Closed Brep” (solid) with the little corners sticking out at the bottom due to the projected edge curves. Note that this is a fragile model because it uses three copies of List Item to select specific edge curves and a bottom point, so will break easily if you simple reverse the order of connecting some wires. (21.5 KB)

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I didn’t get those corners sticking out, not sure if something got lost in translation. Also I was able to use Join Brep with a 0.1 tolerance after all and it finally worked. Thank you for looking into it.

The corners sticking out are a result of projecting the edge curves, which have an “overhang” that results in a vertical edge at those corners when lofted. Using a different method to get those flat back surfaces would avoid them. The only surprise to me is seeing a “Closed Brep” result that has “fins”.

Try to learn as much as possible from each thread before starting new ones.

Here is another approach but it involves picking an item, so it’s not a general (10.4 KB)