Line connection

grasshopper
unhandled

(Adcarldg) #1

Hi everyone,

I m learning grasshopper by my own and trying to understand a few things about the list

I am actually doing this tutorial (link below)

My first question concern the connection of a line (see the tutorial at 5:35min)
I don t understand why i don t get the same result when i connect my line to the two different explode component.

I think i should have the same result as the second option for both. please see the shotsreen attached

My second question concern the extrusion of my polygon (see the tutorial at 6:50min)

I don t understand why i need to join the curves to able an extrusion in the two senses.

Thank you by advance for your help

Adrien


#2

Check your connections. It looks like you connected the endpoint of the line component to the wrong component (it passes very close to the correct place)

I am not sure I understand your second question.


(qythium) #3

Your 1st question has to do with the Explode component automatically grafting each input:

  • 1st Explode takes in a curve and returns a single list of N curve segments,
  • 2nd Explode takes in those N curves and returns a Datatree structure with N branches and only one item per branch (since the segments can’t be divided further)

This means the downstream components will match things up differently - basically inputs are matched branch-by-branch and only broadcasted across lists:



I’m afraid I don’t understand your second question either.


(Adcarldg) #4

Thank you very much for your answer but am really sorry it doesn t really help me

What i try to understand is how the list work.

In your first exemple I guess the vertex number 0 of the first list connects to the vertex number 0 of the second list. and the 1 to the 1 etc…

In your second example i don t understand how it works…

Then when i bake the lines I obtain infact 7 lines but not the lines i was expected.

see below what i expected : (sorry for my basics drawings in red)

What it happens is different and i don t understand the logic.
They don t reach all the points in a logic order and i find sometimes some lines which overlay and has the same length.

What i tried to understand in the previous tutorial is how the list work to connect the point and in which order.

Thank you for your time

Adrien


(qythium) #5

What happens is that each of the (N=1) branches from the grafted component B is being matched up with the (N=7) branch from component A. So there are 7 lines being drawn per branch, each connecting the same vertex of B with all 7 vertices of A. This happens 7 times for each branch of B, for total of 49 lines.

I realise using a closed polygon as an example might have been confusing, because the start and end point is repeated. That’s why you get N=7 for a hexagon, the center point isn’t involved at all.


(qythium) #6

It is a tricky thing to get used to for most beginners, you can play around with the following:
datatree-matching.gh (9.7 KB)


http://grasshopperprimer.com/en/1-foundations/1-5/2_what-is-a-data-tree.html