 # How to draw a tangent line using Divide Curve?

PourForumGHDivide.gh (4.9 KB)

Hi!
I am using Grasshopper after a long time without using it.
I have a very strange problem, maybe this is evident but i don’t know how to solve it: what i would like to do, is, from each point that divides my curve, is drawing the tangent vector to the divided curve, and from each tangent vector, drawing a segment with two points, in order to have the direction of each tangent and the segment line from this. I really don’t know how to do this, we have at the command “Divide Curve”, in the output, “T”, that is for tangent vector, but, i tried from this output to use the commande “construct point”, or "deconstruct point’, too, i tried to connect at this output the command “Vector Display Ex”, but i see no vectors, and i don’t know why, could you please help me?
Thanks so much I don’t understand what you mean, BTW check this…

PourForumGHDivide_re.gh (10.0 KB)

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Hi Kim

Thanks so much for the answer.
Well, i think i did not explain well what i wanted.
I join you here the screenshot and the new GH and Rhino file: what i would like, in fine, is not the tangent, but, if i imagine how i did this in Rhino, the workflow would be:
Imagine that point 0 is the first point of the divided curve
Imagine that point 1 is the second point of the divided curve
Imagine that point 2 is the third point of the divided curve

1. Doing the first line line with point 0 and point 2

2. Construct a point at the middle of the precedent line

3. Construct a new line made with the precedent point (middle), and point 1

4. Make a little bit longer this line, in order that i can adjust the center of a box along this direction given by this line

Repeat this workflow for all the points of the divided curve, so, all the lines would be:

1. Line with point 0;2 (as we saw before)

2. Line with point 1;3 (and idem, the aim is to place the same box with the same workflow than before)

3. Line with point 2;4

4. Line with point 3;5

5. Line with point 4;6

6. Line with point 5;7

7. Line with point 6;8

8. Line with point 7;9

9. Line with point 8;10

10. Line with point 9;11

11. line with point 10;12

12. Line with point 11;13

13. Line with point 12;14

14. Line with point 13;15

15. Line with point 14;16

16. Line with point 15;17

17. Line with point 16;18

18. Line with point 17;19

19. Line with point 18;20

20. Line with point 19;21

21. Line with point 20;22

22. Line with point 21;23

23. Line with point 22;24

24. Line with point 23;25

The aim is to place the same box with the same workflow for all the 24 lines we have constructed before.
In the file i give here, i placed the 2 first boxes.

I imagine that to do this in GH, i have to create lists, but i don’t know how?
Thanks so much if you can help me!   PourForumGHDivideBis.gh (6.92 KB)

Sorry, i forgot to join too the rhino file, it is here! PourForumRhinoGHDivideBis 001Rhino6.3dm (172.1 KB)

You can use dispatch and shift list if that what you want

PourForumGHDivide.gh (10.2 KB)

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Hi!
Thanks so much! It is what i want, but, as i put here the new screeenshot and rhino file and GH file, what i would like is to have the perpendicular line for the two dispatch lines, for exemple, i want this line on each point: point 0, 1, 2, 3, 4…
I tried to do this in the new GH file i give here, using “Shift list” for the two exploded curves, but it seems i made a mistake because it does not do that. Too, i would like to make longer the little curves, and i would like to know too, the worflow i would have to use if i want put the same box, or, the same polysurface, on each, around the direction of each little curb.
Thanks so much! PourForumGHDivideBis.gh (11.2 KB)
PourForumRhinoGHDivideBis 001.3dm (176.1 KB)