Problem with NURBS intersection

[wfmoralesp]

Hi everyone,

I'm trying to import a point cloud and create a nurbs surface I can work with. I succeeded by importing the XYZ points and applying "Geometry/Create/NURBS surface/by Points". This creates a surface whose borders don't fit to the extension of the point cloud , and that I need to trim it:

1.png (116.9 KiB) Viewed 3738 times

I created a cube with the dimensions I require, so I could trim it and erase the surplus. Four of the surfaces of the cube 'cut' the initial surface:

2.png (134.18 KiB) Viewed 3738 times

I applied the "Geometry/Edit/Intersection/Surfaces". This unfortunately cuts 3 surfaces only:

4.png (36.55 KiB) Viewed 3738 times

Therefore, the surface is not completely trimmed as I need and I don't know what it might be happening, any idea will be appreciated.

Thx,

Ferney

[escolano]

The surface created 'by points' could have a lot of internal oscillations, and this could difficult the convergence of the numerical algorithm of the intersection surface-surface.


Maybe you can try some trick in order to create the missing intersection line.
For example could try divide the auxiliary cutting rectangular surface (Geometry->Edit->Divide->Num divisions) in the vertical direction.
Maybe then some tolerances change and you will be able to get the wanted curve (or some part).

you can also try to create and approximated intersection curve calculating some interpolation points (e.g. of intersection of the lines created dividing the rectangular surface) (Intersection curve-surface), and then create the interpolation curve with Geometry->Create->Nurbs line and click the points to be interpolated.

once obtained this curve you could use it to trim the terrain surface (the curve must lie on the surface with some tolerance)

If you are unable to do it attach a zip with the GiD model to test it.