Looking for design (make nice diagrams & line drawings) software.

I have a project that needs some line drawings. The kind of diagrammatic drawings that you would see on a patent application, with 3d views and exploded views and lines and arrows explaining what each thing is. I’m on a macbook pro, or if necessary, on a mac desktop.

I don’t want to invest days in learning how to use the thing, cause I’m taking like 8 to 12 images, but I’d like a good outcome. I could do it with a ruler and protractor, but it would look like hell compared to a good design program.

What do you suggest?

Sketchup. Very short learning curve, extremely powerful once you really get into it, and totally free. Lots of great tutorials on YouTube if you need help.

Yep, SketchUp.