How to draw connected tubes?

Question

I want to draw tubes like the blue one on the image. I was wondering if there is a tool to draw such kind of tubes?

Answer 1

You can begin with vertices extrusions:

Give your object a Skin modifier and a Subdivision Surface modifier (at a subdivision level of 1):

You can change the vertices radius in the N panel (or select the vertex and press CtrlA):

When you're good, apply the modifiers. You can then simplify the topology with X > Limited Dissolve (and tweak the parameters in the Operator box).