I used TexMod to view and extract textures in realtime as they load into memory. It's an old but reliable trick, especially for emulator and older games.

I'm assuming you used a BMS script to extract the files from the game? You should be able to open .pak with some tools (for Quake I think?) or just another BMS script for it.
I have lost the files of my experiments when my old PC died, but I recall that I had managed to extract some files. The models are in .DFF format and the textures in .TXD packages (it's the format used by GTA, since the game uses the Renderware engine as well) but was never able to find tools (or Blender plugins) compatible for whatever specific version of the engine MS3D uses. Dunno, this info might be useful to you.
That said, if it's textures you're after, the easiest choice is using TexMod or something similar like NinjaRipper.

How did you manage to extract the textures from the game? I've been driving myself crazy trying to find a file opener for MS3D's .pak files