I need help to search some idea of engine for a RTS. I need a good game engine minimum supporting directx 10 or 11 ( if possible). I have money to pay but not so big. If possible to have a option to make it online like an mmorts. I think if you find an engine not online, i can modify it to install online i am a good programmer. I have tried spring, but this is sharing your game and all player can join it and play free, but me i want to start business.

Pretty much any engine would work. Unity could work, so could Ogre. It's a pretty open topic. What language are you planning to program this game in?