Sure Esther. 

You keep the rights to anything you put on the site. Its your project, your IP. I haven't seen any 3D content on it so far. There are a lot of comics tho. Pretty much anything you can create and distribute. Some of the top funded projects have been video games. One was the Pebble smart watch, kind of like a smart phone. The inventor earned millions from backers on kickstarter. They used to have a page that showed the highest funded projects to date but I think they've redesigned the site a bit since last time I was there so not sure where that page is now.