Notches in tube

I have created a simple tube and want to put two notches on the top of the tube and two “tabs” on the bottom of the tube so when I make four of them with my 3D printer, they will fit together and interlock so they don’t twist.
I can’t figure out how to find the center of the tube on top and make guidelines that will allow me to cut notches on the top and I can’t figure out how to make the “tabs” at the bottom the same size and position on the bottom…


Simplest way is turn on Hidden geometry, View/Hidden geometry, and draw edges to suit what you want.

1 Like

Awesome thank you.
wasn’t sure what hidden geometry was for. Now I do.


@Box is clearly faster on the draw. Here’s another look at the same kind of approach using symmetry. Proportions can be adjusted at any time: