Widescreen Gaming Forum

Spring (formerly known as TA Spring or Total Annihilation: Spring), is a full 3D open source RTS engine originally created by the Swedish Yankspankers, intended to bring the gameplay experience of Total Annihilation into three dimensions.

Works on both Windows and Linux

Download Here

Features
Some of the defining features of this game are:
• Large battles, with support for up to 5000 units per player. (How playable this is depends on the cpus that are running the game)
• Unlimited resources.
• Allows the user to control select units in an FPS style.
• Ability to handle "large" maps.
• Fully 3D camera view, allowing for complete freedom of movement.
• Easily interchangeable AI and Mods.
• Realistic 3D trajectories for projectile and missile weapons
• Fully 3D air combat.
• Detailed terrain. Some maps are directly exported from terrain rendering tools such as L3DT and Terragen.
• Deformable terrain (example)
• Compatible with unit files from Total Annihilation, allowing 3rd party units to easily be moved into Spring.
• Up to max 16 players online.

I must say, that looks pretty good. :)