# Grasshopper test

Hey Guys,

for my Bachelorthesis I want to modell a dome, constructed like an translational surface.

I managed it to create the grid, but now my problem is to create the “ground ring” (ellipse) with grasshopper.

I tried to cut the grid by a plane, to receive the intersecting points of the grid an the plane, so I am able to connect these points, to get the “ground ring”.
The problem with my Pointlist is that they are not i the correct order, so if I want to connect these points, the lines goes form the one side to the other. So is there any possibillity to sort the pointlist?!

Unfortunately I am not so experiend with grasshopper. Is there anybody who can solve this porblem?

However, have a look at attached.

split with plane.gh (36.7 KB)

Hey Tim,

Here is the file:

Translationsnetz (Vektoren).gh (17.3 KB)

I have tried it your way but it did not work. The problem is that the points of the ring are not in the correct order. I tried so other variations to solve the problem.

I consider that I have to sort the list in the following way to draw the ring:

1. I have to sperate the list in 4 different lists.

``````     coordinates  (x/y)
``````

List

1. ``````       +          +
``````
2. ``````       -           -
``````
3. ``````       +           -
``````
4. ``````        -          +
``````

so I can draw a polyline from each list to receive the ring. Is it possible to construct something like that with grasshopper? Do you know what I mean? Thanks in advance for your held.

In the file I uploaded is an example how to sort in a „circle“. If your points are in different branches, flatten them.

And also an example how to get a curve from a surface and an intersecting plane (like what I think you want to do anyways)

I can have a look at your file tomorrow

You get the bottom curve twice, once from your curves intersecting with the plane and once from surface intersecting with the plane.

Translationsnetz (Vektoren)_re.gh (21.2 KB)

1 Like

Wow this looks awesome, thank you so much.

But now there is another problem. I need the intersection points of the grid, because the lines between the gridpoints have to be straight and not bent.

I tired to get these points by linking the curve/curve-component into the item-component, but that did not work.

Is it possible to do that?

You have your points from dividing.
Cull the points lower than the plane. Merge these points with the intersecting points. Sort along curve (use the curves which you divided as guide).
When I‘m home I‘ll upload the file

like that?

Translationsnetz (Vektoren)_re1.gh (29.4 KB)

Hey Tim,

Yeah that is exactly what I wanted.

Thank you so much, you are my savior

Ok, there is another little question.

Now I want to generate a surface on each mesh of the grid.

So a surface is normally generated through 4 points, but how can I set the edgepoints of the surface?

Or is it possible to generate a surface between two vectors? I couldn´t find the component.

Or can I generate a surface trough my grid-points and then divide it with my grid.

Do you understand what I mean?

I installed the grasshopper plugin GeometryGym. With that i was able to split the curves of the grid into lines.

Is it possible to generate a surface between these four lines an do it like that vor the other meshs?