Creating a 4 branch manifold with set endpoints

[TigerMike]

Are you trying to achieve something like this?

If so, check this out.

Spline between / across front and top planes

Hi, Here is a possible way, with splines on two orthogonal planes to define 3D edge to sweep. A few hints: you need to add the external fillets at the pipes junctions before the shell command, in order to get smooth edges inside the pipes the order of the fillets 01 and 02 is important, as well not including tangent edges for fillet 02. I started with a small radius for fillet 02 because otherwise it fails before disabling tangent edges I applied a 0.99 scaling factor to the center pipe to g…