# Line measured on a surface

Hello everyone!. I have a small problem with grasshopper that has taken me several hours, but that I have not been able to solve. I will be grateful if someone can help me.

I have a curve on a surface and I would like to find other points (p1,p2,…pn.) on the surface. The points (p1, p2 …, pn) must be at a distance D1 on the surface. In my code I am using the intersection of a line and a circle of radius R to find these points. please, see the figure below.

My problem is that the line is measured along on a V axis and is a point to point distance. However, I would like to measure the line on the surface. Does anyone know how I could do this?

In other words, I would like to measure the distance from one point Pn’ on the surface to another point Pn on the surface, but as if I were walking on the surface.

Shearin Rhino.gh (22.2 KB)

Edwin Ros

I don’t think your 3dm file uploaded properly, maybe internalise the geometry next time.

I think you are looking for the project tool?
You can project your curve onto the surface and then measure the length of the new curve.

How do you want to measure the distance along the surface? The shortest path, parallel to a plane, or ???

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Hi Christopher,

Than you very much for your answer. I think the projection tool could help me. But now I only need to define the length of the projected line on the surface. Any tools I can use for this?

Hi @edwinrg54,

There is an evaluate length component and you should set the normalize to false.

This?

project.gh (14.2 KB)

Hi David,

Thank you for your interest. I would like to measure and fix the length of the line projected on the surface.

Any idea of how I can do that?

this is a way

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Hi Vikthor,
Thank you very much for your help. It seems that is what I need.
I copied your file and I tried to simulate your code, but I have a issue whit the Line box. When I try to generate the lines between DivDist and SCX, the Ln generate many lines. Any idea of how can I solve that?

Thank you !

try that the insection is at a point for example

or do this

project.gh (12.6 KB)

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