hey everyone,
i'm trying to set up 2 deformed nurbs cylinders and combine them to create one pipe that splits around these buildings (as a background, the pipes will be textured transparent and will be used as a collider for particles so it looks like stuff is flying around the buildings). the problem i'm having is trying to fillet the pipes together, i don't have much experience with nurbs so it might be a trivial mistake. i'm selecting the outermost isoparm of the cylinder to be attached, then projecting it onto the surface of the pipe to connect to, but when i try to trim the projection on the to-be-attached-to pipe, it doesn't let me select the cylinder (even when i select it then go to trim, it deselects it). am i doing something wrong?

here's the layout of the pipes followed by a wireframe of the part i want to attach.





thanks for the help