Hello everyone,

I'm trying to draw a "spline on surface". But when extruding a surface instead of 1 full surface I get a surface made out of many surfaces. This happens because my initial sketch consists of 2 splines and a straight line. This makes my life very complicated because the " spline on surface" becomes very hard to manipulate, extremely hard.

But if I extrude a surface from just one spline, I get a normal surface, and a "spline on surface" is very easy to make.

Is there a way I can make a few surface become one whole surface?

Thanks alot in advance, I've been struggling with this for two days. Picture attached.

EDIT: The surface still devides into 3 surfaces even though I make the splines and the straight line co-linear:

Example: