Hello, I like to present you my open world sandbox game, which I developed in the last years.
It uses an automatic world generator to create a unique world via a seed:
The world is made out of voxels which are saved in a giant octree. Parts of the world are loaded when needed. The voxel resolution is very high. I use 0,25 m per voxel. Through compression it is possible to create very big landscapes (up to 25 km²). Despite this the world remains totally dynamic. So if you place dirt, grass will grow on the surface.
The world generator creates different types of climatic zones. Here is a screenshot from the polar zone:
And here is a screenshot of the desert:
If you are interested, you can check out my homepage:
http://www.staudsoft.com/index.php?id=66
I am also on Indie-DB:
http://www.indiedb.com/games/staudsofts-synthetic-world
And if you want to see it in action: