I'm using Solidworks Professional, and as you know have limited sim capbability.

We  manufacture plastic fuel tanks for the offroad industry.  New EPA regs  require most of these vehicles meet air quality standards, ie having  carbon canisters, low permeation tanks and hoses, fill level shutoffs,  vents, and all.

Part  of that standard is that tanks cannot be filled more than X, and after  filling to the X level, if the tank is tipped a certain number of  degrees the vents cannot be covered by the fuel.  If this occurs the  fuel level (and volume) needs to be recalculated.

There are numerous other factors that go along but this is just a start.

My  question, is there a way simulate this either using Solidworks or Simulation, do I  even need to use Simulation, will an upgrade in software be needed.

I  have several ideas using combine and or maybe a plane and a known  volume and cutting that volume with the plane and recalculating the volume.

One suggestion I got in the sim area is the use mold core feature.  I've seen some videos on the web doing this, and even did my own version.  What I did was insert a  rectangle (fluid) which was bigger than the tank, mated with the front and side planes. Then did the mold core thing.  Matiing in just two directions allows movement of the liquid level up and down giving me the volume at that height with a rebuild.