OpenCity is a free and open-source software 3D city-building game started in 2003 by France-based Vietnamese programmer Duong-Khang Nguyen. The game mechanics are similar to Simcity, while the game developers don't strive to make it a direct Simcity clone.

OpenCity is a free and open-source software 3D city-building game started in 2003 by France-based Vietnamese programmer Duong-Khang Nguyen. The game mechanics are similar to Simcity, while the game developers don't strive to make it a direct Simcity clone.