I’m trying to figure out a better way to select subsets of Brep faces based on their continuity, and in particular, tangent faces. David helped me out with a C# component that I had to put in a loop and hook-up to some Topology analysis Voodoo, but heck, it’s messy and takes too long to process ! I’d be surprised if there wasn’t a component in a plugin out there somewhere that would do this fast and easy, just like you would use SelChain command from within Join, and then set ChainContinuity to Tangent.

Hi David, , If you remember, I managed to make a tree with, for each face of a BREP, the list of faces which are tangentially connected to it, and with your help, I got lists of tangent “chains” of faces. It required using a C# component and a loop… [List%20chains%20of%20tangent%20faces] Maybe this could be a useful extra output for the “Topology” component. This is particularly relevant for bent metal parts where it is useful to get the “Intrado” or “Extrado” skin to flatten it. [Intrado]

Hello, I believe this might be useful for myself, so I made script solving this. I haven’t tested it much, but in the example it seems to work: Please also note that there is no perfect g1 or g2 matching in reality. [CheckForTangency] CheckForTangent.gh (15.1 KB)

Hi TomTom, Excellent ! Thank you so much.

Is it possible to edit that script so that it outputs a structured tree when there are multiple Breps as input ? Multiple solids.gh (699.0 KB)

sure: CheckForTangent2.gh (19.7 KB)

Hmm… it doesn’t seem to work with my data set. Something is wrong.gh (694.4 KB) By using “Brep Join” on the output, I should get a single Brep in each branch, right ?

"I should get a single Brep in each branch, right " not necessary. well, doesn’t work then. :slightly_frowning_face:

Well, if each branch represents a set of tangent surfaces, they should become a single Brep after “Join”.

as I said, haven‘t tested it fully. I spend less then 60 minutes which is a lot for free help in a forum. I believe its more about the idea rather then providing full functionality. Basically you can use this script and devellop it further.I fully commented so even if you dont understand c# you will get the idea from my notes. I also would like to help you further, but I do have a full time job so I cant simply spend 60 hours to it, which is a realistic timeframe for a well engineered functionality like this.:wink::slightly_smiling_face:

Select tangent faces of a Brep?

Grasshopper

TomTom (Tom) April 4, 2018, 1:35pm 8

maybe these paths are more natural:

CheckForTangent3.gh (20.1 KB)

Grasshopper unroll surface component

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Select tangent faces of a Brep?

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