SpudFiles

Since you want something free I would go with Google SketchUp. Personally I don't like it. I mean its good for something thats free and simple. But I prefer TurboCAD. It's around $100 but I like it much better than SketchUp.

So something free thats pretty good is Google SketchUp. But if you want something more advanced and that can probably do more i'd sugest investing in a paid one like TurboCAD or something else.

One of the big advantages to Sketchup for this site is one of the members has made an extensive library of parts so you don't have to spend all day rendering a 2 inch PVC T.

It's even a sticky to make it easy to find.
http://www.spudfiles.com/forums/sketchu ... 17755.html

One of my favorite launchers is in there.

I have used sketchup and I was thoroughly disappointed. I learned on Auto desk Inventor which is not incredibly hard to learn but can pricey. It is all I use now.

have you looked at valves sdk? i use their map editor hammer as a cad program all the time, it is really easy to learn and use.

OpenSCAD works for me