> the first versions until idTech 5 were open source and a number of important engines, like Source, derive from it

Huh? They were made open source when they were obsolete, Valve did license ID IP for the first Half Life but they paid for it. And that evolved indeed in Source.

It's also missing games, like American McGee's Alice.

Thanks for the share ... never knew so many great games were built on idTech and engines derived from it.

Source being based idTech is a pleasant surprise.

Very interesting tree. Today I learned that the engine we used in college classes, ACKNEX, actually wasn't an idtech derivative. I could have sworn.

Machine games and Arkane studio use IDtech.

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