Don't know how I ended up in the FPSC Models board, but I think I can help out with the theory of this thread.
I wouldn't put it past stock FPSC to get this accomplished. There are some commands in PB that will help to give a convincing illusion for this, though.
So, the problems we're facing here:
1) Make the door (or object in general) open through mouse movement, while the mouse button is held down.
2) Animation should be proportional to the speed of the mouse movement.
That doesn't sound too hard... but I've neglected to include the physics, which I won't be touching up on since doors in FPSC could hardly be considered physics objects, they simply lose their collision when opened and resume having collision when closed. For an "illusion", I think that should suffice.
The possible solutions:
1) When "mouseclick=2" (or 1 for left-click) capture the internal variable "$MMX" (or "$MMY" if you want vertical mouse movement) and apply a percentage to it (perhaps 20% or 30%) to lower the value.
2) Increase the object's (door's) frame by the calculated amount of mouse movement, assuming it wouldn't go past the object's max or min frame for the animation.
For dealing with removing or restoring collision to the door (to make it "open" or "closed"), I would go with something along the lines of, if the current frame is in the last 50% of animation frames, remove collision. If the current frame is within the first 50% frames, restore collision. (Of course, this is assuming the animation goes from closed to open)
Hope that all made sense. Maybe one of the PB scripters here can give it a go and let us know how it went.
The one and only,
Only those who sow the seeds of their desires will reap their benefits later.
However, I have seeds of my own to tend to. I don't have time to be someone else's watering can.