Brep | Brep Intersection won't return the full Intersecting curve between surface and pipe

I’m trying to get the intersection curves using a brep|brep component between a pipe and some surfaces but one of the intersection curves is incomplete as you can see here:

How can I get the full intersection curve to detect correctly?

The file is here with the breps internalised:
Brep Intersection (294.7 KB)

Not sure why it happens but you can connect the two curves like this:

Brep Intersection Issue_2021_Jul2a
Brep Intersection (292.0 KB)

Yes, that is the sacrifice I might have to make, however this issue happens with many other surfaces along the pipe so I would have to develop some algorithm to blend curves within a given tolerance or something.

Weirdly enough when I bake them and try to split them in rhino, it doesn’t work unless I move the surface a small given amount. Really weird.

Understanding why it fails would be the most important thing so I would be able to get the precise curves to be used later in the file.

That’s always best. It’s a peculiar surface and this code fragment doesn’t show how it (and the pipe) was created,

there’s a little self-intersection on the bottom-left side of the pipe:

this comes from my personal experience and nothing more: whenever I execute split/booleans/trims of surface where the split-line happens to be exactly over the existing seam of one of the geometries to be split, that splitting/boolean operation fails consistently

in your case, I see that most of the seam-line of the pipe travels where the splitting line of the planar surfaces will be:

I would generate a pipe along that very same central axis -without self intersections- in such a way the pipe-seam lies on the opposite side of the pipe itself, and give it another shot :+1:



I tried to trim the pipe so there was no self-intersection but it didn’t work.

My not perfect but working solution was to either move the surface (far from ideal), extend the surface (also not ideal), or rebuild the surface which is close to ideal, just not 100% perfect but good enough :slight_smile:

If it"s alright, you can move your second brep slightly to avoid touching with the seam of the pipe surface…

Brep Intersection (293.0 KB)

Good observation but that’s not where the intersection is failing.

@nicholas.ziglio, why give yourself credit for “Solution”? Prove it!
No one learns anything when the OP says “Never mind, I solved it myself.”

Because it works.

Brep Intersection Rebuild (300.4 KB)


I don’t know how these surfaces were created but wonder if rebuilding base curves with standard GH components would have the same effect?