It's been a few years since I've bought a Lego Mindstorms NXT 2.0 which comes with the Technic style pieces.
There's beams, axles, rods, connectors... but the majority of the times when I'm building (mymy own designs, not following instructions), I wonder which is the right part to use. There are usually several options and I never found what is the exact intended purpose of each one.
Is there a website, document, or anything that I could use as a reference for what each part in the Technic set is meant to do?