From Quake Wiki
Models are 3D meshes used for the monsters, weapons, items etc in Quake. In Quake they use the .mdl file format.
The original models were created in PowerAnimator. They are/were sometimes referred to as "Alias Models" which seems to originate to this. Probably to differentiate between "bsp models" like the ammo pickups and the "alias models".
The textures for the models were created in [Deluxe Paint|http://en.wikipedia.org/wiki/Deluxe_Paint].
http://forums.insideqc.com/viewtopic.php?f=13&t=5676 http://www.gamers.org/dEngine/quake/QDP/makemodels.html http://www.gamers.org/dEngine/quake/spec/quake-spec34/qkspec_5.htm http://www.insideqc.com/qip/q1/qfix.htm