While it requires signing up in order to use, OnShape is pretty damn awesome for a browser-based solid modeling program.
The free account limits you to 10 private documents, that don’t get published for others to be able to look at, and public documents don’t seem to have any kind of limit.
This is really an awesome tool for those who want to go beyond the abilities of something like TinkerCAD. http://www.onshape.com
There’s a 5Gb limit on free account, but it’s plenty enough. I was converted on Day 1. Wonderful tool for makers and top notch support. The speed at which they keep releasing new features is nothing less than amazing.
They really have come a long way since their initial beta. I was only reminded that it existed by @Michael_Memeteau 's little teaser post. I signed back into it and it’s amazing. It’s made by a lot of the engineers who worked on solidworks, so it follows a lot of the same paradigms. I like though, how they combined “extrusion”, so you don’t have two tools, now you have one tool, and you can tell it if you want to add, subtract, etc.
The only thing I don’t like is their mating feature in the assembly mode. I’ve gotten better at it, but it still takes me longer to snap things together than it would on solidworks.
And they just released a great ‘webinar’ on the basics of design intent. A great one for people designing or modifying repraps/3d printers. (forgot the link :P) :