liquid fill
3D scale the bottle so that it is slightly larger than the inside of the
original
[modify/object/3D Scale] + Shift(to clone)
Use the Boolean to cut off the new bottle at the height of the liquid
At this point, you going to have to spend some time in the mat. editor. Assign
a different surface to the top of the fluid (very important). For example; Auto
reflective, Bright specular highlight ( you may also want to use the specular
mapping feature to simulate ripples) and make it almost completely transparent.
The body of the fluid will be the most difficult. If I had to see the body of
fluid, I would loft a couple of "ribbons" and make them completely transparent
with bight hilight. Maybe even morph them. By putting them inside the body of
fluid and rotating them, it might create the right effect. Of course that would
take some time in the Mat. Editor to get the surfaces just right. Also, if you
hit this thing with a ray-traced spotlight, go to lunch. It's gonna be a while
<g>
Don't wave the liquid, but bump map it.