Intersection (anti-parallel)

Hey everybody,

I'm in trouble with cutting curves at specific intersections points.

For my project I rotated curves along an axis to create a column developing out of my roof.

My first try was to extend these curves up to their intersection and then cutting them at these points and loft them again.

But they are partial anti-parallel and because of that Grasshopper doesn't find their intersection of course.

Maybe there is another way to solve this problem.

I hope again that you can help me.

Thank you very much.

Attachments:

Grasshopper Iintersection.jpg, 621 KB
Grasshopper_Forum_Intersection.gh, 39 KB

Replies to This Discussion

Permalink Reply by David Rutten on March 1, 2016 at 10:10am

Erm... the last part of your file was orange because a polyline was missing, but I assume that it's the LLX component that was giving you trouble.

I don't have a very good solution, but it seems that (at least in the current case) the missing 'intersection' points ought to be exactly in the middle of the two (anti)parallel line segments. If that's always the case, you can create a second list of average points, and then fill in the gaps in the intersection list from this second list (just like in Jurassic Park they used frog DNA to fill in missing Dinosaur DNA, and that went swimmingly).

Attachments:

intersection_and_averages.gh, 32 KB

Permalink Reply by Philipp S on March 1, 2016 at 10:46am

Yes that's it. Thanks a lot for the quick reply.

I tried to evaluate both curves to get the average but the result wasn't real good.

But there isn't another way to get something similar to this without using the extend component?

Otherwise I will continue using your solution.

Thanks a lot!

P.S.: Can you please explain me what the combine data component do? I never used it.

Permalink Reply by David Rutten on March 2, 2016 at 2:44am

Combine takes in 2 (or more) lists of data. It then builds an output list where each element in the output is the first non-null element from all inputs. It was designed to be 'the other end' of the Sift-Combine workflow, but it can be used on its own.

Permalink Reply by Philipp S on March 1, 2016 at 11:22am

Ok, I get it and the result is sufficient.

But my biggest problem is to get a volume out of this.

I need to thicken it up but I don't know how...

For my base geometry I simply loft through all curves. But neither I can offset all curves nor the geometry.

I hope anybody has an idea.

PLEAAAAASE!

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