NeoAxis Game Engine

NeoAxis is a recent Game Engine, built on top of the OGRE Open Source Game engine.

While OGRE can be used as such, the NeoAxis group is wrapping it inside a more complete authoring system, not unlike Unity3D, which is a real advantage for artists, who are not always interested in the hard-core coding that goes on in the background. I believe that this pertains for most architects as well, hence the success of Unity3D and SketchUp.

NeoAxis runs on Windows and can create both standalone games and web applets. You can use the free non-commercial version or buy a cheap $100 Indie license.

There are people working on a plugin for SketchUp to get models into NeoAxis more easily: