/vr/ - Retro Games

As we all know, most of the Doom monster sprites were done by drawing over a model or some other RL photo
But how did Raven do things? How were the Heretic and Hexen monsters were done? For example Iron Liches look like they could very well be done from a 3D model, but how was a Golem or an Ettin made? As well as others.