And Valve has its own versioning system. They just don't openly publish those numbers. Don't get hung up on the fact that companies are appending numbers to the end of their engine names and Valve is not. Unless you're a developer, that number is totally inconsequential.Look at Crytek innovating from Cryengine 2.0 to 3.0. Or id going from id tech 4 to 5.
It probably does. They're both binary space partition-based engines. Wouldn't surprise me if simple things like object pickup code are almost identical between both. There's no need to re-invent the wheel for that kind of stuff when you can just copy & paste from a codebase you already own.Well, at least Doom 3 doesn't contain engine code from Doom 2![]()