well, you can make any model with as many different animations as you like. ie fight, swim, jump, run, die, eat clam chowder, ect.

first, you have to export from the modeler that you are using now to MED or Milkshape3d or some other modeler that will allow animation and allow export to 3d gamestudio.

Then, you simply call each animation as you need it. Keep in mind, the more animations (vertex) you have for a model the more memory the model will take up.

as for the roof and floor animation, you can specify each by using a trace to see what material the model is standing on or you can use the my.z and guestimate the height to trigger each separate animation.

you can have different models with the same animation, but it's a little tricky.

as for the hip coord, you can center the model in MED along the crosshairs on the x, y and z axis. that should place the model where is should be in WED.

make sense?
does this help?