Thank you very much for the help provided.
In fact, I need to attach a flat plane to a surface.
And this surface is in a point cloud, but first I think I should turn it into a Mesh.
Note: I recorded the pathologies of a tunnel in a reflected plane, 2D.
And this tunnel is in the form of a point cloud arch.
The Pathologies were recorded in a 2D plane of the Reflected Tunnel
Now I need to draw or attach these pathologies to the Tunnel plan which is an Arc, following the contour lines.
Ex:
