I usually only draw things on paper when sketching initial ideas (I'll fill up dozens of D size sheets during the first two weeks of the build season doing this), or if making a quick drawing to give to the machinists if there's no printer around.
Otherwise on Team 228,
everything mechanically is modeled in SolidWorks. Part numbers are assigned* and official drawings created for every manufactured component on the robot. From there, exploded assembly drawings are also created for some of the critical sub-assemblies, while others are just assembled using laptops with the CAD model open as reference.
Doing this, we were able to machine almost 70% of all components for both of our robots before anything was even bolted together. Ironically, the
battery holders were the first completed sub assembly of our 2009 robots (they fit perfectly into the robot chassis' once they arrived back from the machine shop earlier this week). ;-)
Why do we go this far and model everything now? Because for years we did minimal CAD modeling and relied almost entirely on hand-drawn drawings. Without out a doubt, they worked well. But at the same time, it's a lot harder to tell if there is interference between two components in an assembly when it's drawn on paper instead of SolidWorks. And that came back and bit us. A lot. And because of it, there was a lot of "redoing" parts over again (which frustrated our machinist).
This year, by doing everything in SolidWorks ahead of time, we haven't had to redo anything. On the plus side, we now have an entire binder full of SolidWorks drawings for every part on the robot; so if anything breaks and we need another, we're covered.
* I really did give part numbers to everything. Need another Delrin spacer for the rear mounting of the pneumatic cylinder on the right side of the ball intake mechanism? That's 09-BI-026. Need another transmission housing with corresponding bearing spacer? They're 09-STR-006 and 09-STR-007 respectively.