I attach the file from which I extracted the surface thenso it is not that you understand much...you should attach the model
Yes, because I'm in two different angles and it doesn't really make me create any superfice i.e. when I go to use the command I don't take the lines in tangenzawith any cad.
If I understood your question well.. .
you need to create 2 surfaces (red and green) and then join them
View attachment 68514
ciao @emanuele fat I don't see the file.I attach the file from which I extracted the surface then