(HELP) How to merge numerous polylines into one

Hello everybody,

I need help with merging those 2 polylines into one and closing any gaps between them to be able to create a surface and extrude it, I tried the joint curves component, but it doesn’t get the job done.

Thank you

Close curves, or use end points, create a line between them and join all together

ok great, did it

Any idea how to approach the top of the model I want to build as in the sketch

Upper control points -> average
Move mid point in z.
Shift control points
Graft shift and normal control points
4 pt surface
A = control points
B = shifted control points
C = mid point

1 Like

Here we have another solution using Shell Polysurface in pufferfish plugin.

Shell-Polysurface.gh (12.8 KB)


I am sorry I don’t fully understand as I am a beginner, can you be more specific please

Here’s the file if you want to edit it
Model.gh (10.3 KB)

thank you for your time

very nice, thank you, but isn’t it possible to do it without plug-ins? I have to do this assignment without any plug-ins I think

Personally, I don’t know what it means to work only with native components without using a plugin in the use of GH.
GH is an open platform for applying various plugins and Kangroo actually has been shipped into GH and is no longer separate plugin. Anyway…:wink:

Model_reV2.gh (12.3 KB)


wow, very nice, thank you very much for your continued support. You’re quite the whizz in grasshopper, how did you get so good? I want to improve, what would be the best way for me to do so? I read the mod lab book and applied the examples, and I bought this book https://www.ideabooks.nl/9788968010392-evolution-architectural-design-using-grasshopper, but didn’t start it yet, any other ways I should pursue other than books?

Like anything it takes time and practice, HS-Kim has been here for years problem solving and has now seen most issues several times. If you want to learn Taekwondo you can read books and watch videos but at some point you’re going to kick things, 1000’s of times to get proficient.


… Sherifusa can get the same skill when putting time and effort in it. There are many people here who can solve these problems and this is no superpower nor rocket science.
Most people here simply don’t have the motivation and patience to solve assignments and work for others. This forum is called "Discourse-McNeel, not “Do-My-Work-For-Me”-McNeel. I mean, what’s the point if someone else solves your homework? If you want to get better you need to study and solve real world problems and rather ask for a way to master a problem, not asking for a solution. @HS_Kim always provides an solution additionally which is rare, I just have the feeling that people here don’t get point. For an assignment this works, but how on earth will you solve a real problem with these little snippets. If you don’t understand what’s going on, you won’t be able to solve them.

I would say in this case the native version is nicer= cleaner, the shell messed up the edges (left shell, right native), but I agree to use Plugins and I am often surprised, you seem to know most of them.

It’s not necessarily ‘‘messed up’’, what it looks like to me is that the left one is an offset of the faces on each the face’s normals, which yields a different edge topology, which indeed looks, not nice. The one on the right is an offset of the nodes or vertices which keeps the same edge count /topology. This is common when offsetting on the faces norlamls, instead of offsetting the vertices.