I am looking for a game engine with multiplayer support that allows for players to place objects in the terrain. (eg. in TF2 one can place teleporters, etc... or in minecraft one can place blocks). I don't need the placeable objects to be interactive like in TF2, but I just need an engine that won't make me code this from scratch. I have decent knowledge of Python, PHP, HTML, C++ and C# (and a small knowledge of Lua scripting, although I have only been at it for a few months) so I should be able to handle most engines. I attempted to work with the Cube engine, but unfortunately it wasn't the best match for me. Can anyone recommend another engine capable of this? Thank you.
You can do that with most any engine. You just build it in advance and then use a script to place it and operate it. Unity is a pretty good engine with multiplayer that would do it. You use prefabs, in their terms. If you watch a player shoot some type of bullet, that's the same thing. The player is creating the bullet when he pushes a button or whatever. It was just defined earlier by the developer and then spawned at the end of the rifle and given a velocity.