MasterpieceVR is a professional 3D modeling tool for virtual reality, with the added bonus that you can work collaboratively in multiplayer mode:

The product appears to be a very powerful creative tool, as you can see from these samples of work created within MasterpieceVR:


You can see the complete gallery here. You can also see more MasterpieceVR creations on Sketchfab. Here’s a one-minute promotional video:
To find out more about MasterpieceVR, you can visit their website, where the company maintains a blog and a user forum. You can follow the company via Facebook, Instagram, Twitter, and YouTube.
Another addition to my list of social VR/virtual worlds!