Hi all. I do need to extract the external and internal contours from some BREPs for CNC mechanization and unfortunately I can’t find a viable way to do so. I can’t find a way to merge or “solder” all the faces together so I can easily extract the contours of the shapes. Any help will be appreciated.…

Here is the solution. Now this is the part where I quit because I know the next thing you are going to answer is a new edge-case that breaks this. [image] External Internal Contours_OnlyFullHeight.gh (9.9 KB)

Hi, You have a lot of surfaces that are degenerated (appear to be straight lines). And duplicated curves. [image] This works but you’d better clean the input geometry. [image] External Internal Contours.gh (36.2 KB)

Yes I know, because they are BREPS projected on the XY plane. I just need the contours and literally nothing works properly in this situation, unfortunately. I do attach the original BREPs, so maybe can find a way to extract the contours from the original BREPs: test.3dm (185.5 KB)

Make2D could be a way. [image] External Internal Contours_Make2D.gh (84.9 KB)

I do tried this method, but unfortunately Make2D can’t distinguish between pockets that are not full depth and partial pockets. I do need only the external and internal contours that are passing through the geometry.

This ? There is only one hole that goes entirely through the solids though, others are blind holes, chamfers of pockets. I’m sorry but your original request is far from explicit. [image] External Internal Contours_OnlyFullHeight.gh (52.7 KB)

Thank you for the definition. Much better but still not working with mitered edges. Please find a new file with some mitered edges that are giving some weird results. P.S. For this I wanted to project all the surfaces in one plane, because then I do have the guarantee that I will have the desired c…

I still don’t understand if you want those chamfers to show up of not. I’ve added a test for the direction of the surface, it removes all non-vertical surfaces. Maybe you can use this the other way around, keep only non-vertical faces and project their edges… [image] External Internal Contours_…

It is working better but still not working with any kind of shapes. In this case it is not working with parts that have cutouts: [Shape with cutout] test.3dm (736.7 KB)

@Cumberland Are you talking about something like this? 2d 2023.gh (6.9 KB) [ViewCapture20230814_112444]

No, I do need only the pass-throug contours. The ones where the parts have holes from top to bottom. Drown with the mouse, hopefully it can be understood: [3dd51590047800feaf98112483bc4d297c6bc459] I need something that works with any shape you can imagine projecting the pass-throug contour from…

External Internal Contours?

Grasshopper

Cumberland (Cumberland) August 15, 2023, 7:51am 16

Maybe use the MShadow calculations to cull all the internal edges and join only the external ones in closed polylines?

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External Internal Contours?

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