# How could I divide a double curve surface to equal rectangular mesh?

Hi,

How could I divide a double curve surface to equal rectangular mesh? (The way I tried to use, it does not give me the equal mesh). because I need to put a group of specific geometries in the cross section points of mesh. And also I have another question, how could I face the group of geometry align with the face of the surface (how should I rotate the geometry and use the tangent of the surface) ?
I would very appreciate if someone would advise me.
Thank you.
Zara

Idea 2 Test 1- 06-Feb-2018.3dm (78.0 KB)
Idea 2 Test 2- 06-Feb-2018.gh (7.3 KB)

What do you mean by “equal mesh”?

As a brief explanation; I try to use grasshopper and start modeling a double curvature surface like a “structural Oscillation”, robotic fabrication research by Gramazio& Kohler, ETH Zurich. A double curvature surface with standard elements. The difference is, I am try to define another geometry system instead of brick. So i need to find the points on the double curve surface with the same distance to each other. When i divided the surface with putting the number of segments ( U&V count) , the cross section points that it gives to me are not positioning with the same distance to each other. I try to show my question in the two images that i attach.Thank you.
Thank you.

Surface parameter space (often called ‘uv’ space) is not equidistant. The same is true for curves as well. If you walk across the parameter space in equal steps, the distance between these steps once mapped into the 3D world is not guaranteed to be constant.

You will need to extract the iso-curve at the section you want (or create a section curve some other way) and divide that curve into a number of equal segments. Since your underlying surface is curved in complex ways, the total length of adjacent section curves will not be the same. This means that your elements will be slightly longer or shorter on level x then they are on level x-1 or x+1.

Thanks David. but I have a question. I am in the very first step of my research project, and finally i want to develop my idea and talk about the robotic fabrication, and i want to talk about the standard elements, which means they all have to be the same size. If I do not make mistake, what you mean, is that, anyway, we cannot have the exact distance between elements along the whole surface? Is this what you mean?
Thank you again.

This is true. If you want your bricks to align perfectly at both sides, then you will necessarily have different length gaps between them. This may not be a problem, bricks and mortar as well as other types of stacked elements have some wiggleroom, so if there are plenty of gaps and the gaps are allowed to vary in a big enough range then you can accommodate a certain curvature. If all your elements have to be stacked exactly side by side then you will not be able to have your elements align vertically at one end of your wall.

You’re absolutely right. I, for sure going to define min& max gap between elements anyway.Thanks a lot . I am not good in grasshopper staff, but i try to learn, and i have to go forward step by step. So sorry in advance if it would be a boldly request, but i think i will back to you with some questions sometime, and I would be very appreciated with your support.
Best,
Zara

I’ll be out of office all next week, but after that I’ll be happy to help you further.

Thank you so much . Your support would be a lot to me.

Have a wonderful weekend.

Very best,
Zara

Hi David,

Hope you enjoyed your vacation. Sorry I back to you. I have a question:

How could I put the group of geometries and use the “Orient” for transform the group of multiple geometries from one axis to another axis. It does not work properly when I just put a point in the centre of multiple geometries to define it as a source of it, and I set multiple geometries for the curve. I would appreciate if you would advise me regarding this issue.

Please note that I want extrude them latter. How if having them as Brep instead of curve and then transform them as Brep?

Thank you so much for your time and attention.

Very best,

Zara