How can I made Bézier curves that are not flat?

[TigerMike]

Here’s another one.

Can I make a design that steam tracing line on the pipe with flange and various valves?

Make the most of using the Sweep tool. Utilize the negative space around your pump-flang-valve to create a buck or dummy path for sweeping. This example is on one plane. You can also can add 90" extrusions (or other angles) around the buck as needed to sweep in 3D.