How to calculate specific liquid volume? I'm new to Blender and have a question regarding modeling of realistic scaled objects.
I'm modeling a complex shaped bottle and I would like to scale it (using metric values) to hold a specific volume of water.

More specifically:  


I know the volume of water - 0.5 liters.
I have the bottle model.
I want to know the realistic dimensions in millimeters of the bottle model that would hold 0.5 liters(it's diameter along it's height etc).


Doing this with a simple shape (e.g. cube or cylinder) is easy to calculate but for a more complex object it's not.

Also, is it possible to simulate flow of a specific quantity of liquid? In that way I could fill the model and in a few iterations have the right proportions.
You could use a cube, to scale it that it has a volume of 500ml, calculate the 3rd root of 500 ~ 7.93 (this should be the edge-length) scale the cube to this size.
For a bottle you might want to model a funnel.

For the fluid simulation setup:


Set the cube as fluid
The vessel as obstacle
The funnel as obstacle


For all set the Rigid Body Collisions shape as Mesh.


Add a domain object as domain
Set the rigid body types to passive otherwise they will fall down.
Increase the resolution to ~90 (more would be better but extremely time consuming)
Bake the fluid sim.




After filling your vessel you can use the methods on exact measure as described here:
How to model effectively using exact measurements?.

Instead of pasting all settings I uploaded the .blend here