Creo Elements/Direct Modeling Express 4.0 is a popular 3D CAD choice for leaders in product design who have short design cycles and frequent one-off designs. Its speed, flexibility and responsiveness to change also make it the ideal tool for short-series production runs.
"Download this free 3D CAD software and create assemblies with up to 60 unique parts. Use it as long as you like. Once you’ve registered and downloaded the software, it’s yours to use indefinitely.
I'm using it now to design a linear carriage for my Rostock build. It does pretty much everything and it's fairly easy to use. The app's help system is very well done and includes numerous videos. The video tutorials are really good and easy to follow.
The GUI is very smooth and responsive. It exports .stl files or saves in its own format. You can import four flavors of Step-format files and a couple others.
You need an internet connection to activate it, and you must allow it to re-activate every three days. The only thing it doesn't do is autosave. The full-blown version might do it, I don't know. I can tell you for certain though, for the average person who needs to whip up a part for 3D printing or CNC, it's hard to beat. Direct modeling allows you to type in a dimension and not need to play around with positioning the cursor to reach exactly the right point on the screen.
http://www.ptc.com/products/creo-elemen ... g-express/
