As an indie game developer, I love making 3D games, but have difficulty designing unique/custom 3D assets to use in my games. Modelling programs like Blender and others are great, but I find them a little too difficult to learn and use, especially when I don't want to spend too much time on simply creating 3D assets.
the Block Builder tool is my solution to this problem. It allows for fast and simple creation of 3D models by simply using voxels. It's just like playing Minecraft, except your designing an object that is going to get exported to .obj (or some other format).
Obviously, you could use this tool for anything, but I personally plan to and recommend using it to design small props, such as guns and other items in-game. It would be interesting to see what kind of characters you could make with this tool.
You can either download the latest-release from here, or download the Unity source code and modify the project to suit your own needs.
This project is of course open source, and I encourage and ask anyone who wishes to, to contribute and make this project better for everyone.