I've started working a personal program to design shapes with tubing (and produce G-code for a CNC tubing cutter I'm going to build). It's been roughly 20 years since I was last in a vector geometry ...

Calculate the total surface area and volume of a cylinder with this no-prep geometry worksheet! Features visual 3D diagrams, mixed radius/diameter calculations, millimeter and centimetre units, and ...

gives formula to show if a point is inside a cylinder. It is based on finding a rotation that maps the cylinder axis onto a cartesian axis, and then calculate the distance from the axis.