Whether or not something will sink is pretty simple to calculate.
First off, get the mass of the object and the volume of the object (make sure you have your physical materials specified). If you're working with a hollow object (like a bottle), you'll need to use patches and the fluid volume command to "fill in" the part for the volume (but not the mass!).
Then determine the mass of a chunk of water with the same volume as your object.
If the mass of the water is MORE than the mass of the object - you float.
If the mass of the water is LESS than the mass of the object - you sink.
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Finding the draft height (where the waterline would be) is a more complicated endeavor to handle but can be estimated by taking "slices" of your object until the slice volume satisfies the same criteria as above. You can use your center of gravity tool to estimate the orientation of the object if you're unsure how it might position itself in the fluid.
K. Cornett
Generative Design Consultant / Trainer
