i use mathematica regularly and dont want to use it, i am trying to keep it all under open source tools.

i have done engineering drawing course but it was all pencil and paper, i have drawn few diagrams in autocad in my college days but im not an expert, so i thought freecad might be good, a little playing around would get me up to speed, i have some animation experience in blender(mostly keyframes, if that is what it is called). it would be nice to have vectors so i can scale or animate any way i want, 3d means i can take shots of different angles. i hope this clears my background.

i have used it but it draws very thick lines which i don't want. can you post links to those tutorials so that i can know how it is done, 'cause I'm unable to find any, probably i's searching with wrong keywords