GrabCad is a nice resource for making things that more or less look right, but (as I've just discovered in printed parts from Shapeways) there are some very serious deviations in some models that make them worse than useless for actual engineering.
It'd be great if Autodesk provided a library of parts that are trustworthy and verified correct (even if that was just some subset of GrabCad though ideally it'd be something better).
