Hello Fabio, not sure of what Cull Pattern you refer can you indicate me the time of the video where you are having the trouble so I can assist you. Thanks

at 13:50, tahnk you

Ok, by any chance those repeating points happen at the corner of the surface? If that is the case it doesn´t mean it's wrong as you will have one point for each curve meaning two points will be at the same position. You just need to make sure that those overlapping points, in fact belong to a separate branch.If the points that are repeating are not on the corners I should have to take a look to a screenshot of how you have set up your definition to see if there is a problem with the list grafting or something else.

I tried once again and the problem involving points went away, I must have missed something. The other problem with the cull pattern and the equallity parameter wich was making impossible to select only the points that were touching the curves, I resolved using "smaller than" instead of "equality" parameter, now I'm facing another situation, my grasshopper version doesn't have the "planar srf" option, do you know how to go around this?thank you a lot.

What version are you using? The planar Surface component is a standard one, you could try to use other surface component to build it but it would be not that clean.