Well, bots currently have a radius and a mass. Density is easy enough to construct from that (mass / (4/3 PI radius ^ 3)).
Currently, body is the only substance that effects bot volume and thus radius. Shell and body are the only things that effect mass.
So presently a bot can increase it's density by building lots of shell, but there really isn't a way to decrease it's density along the same lines.
That's what I invisioned float sacs for. float sacs would be massless bubbles that increase volume without increasing mass.
Also, in physics, all forces operate on added mass, which is a property I can only find alluded to in several places, so I may be off with it.
Basically added mass means that for an object in a liquid to move, it must accelerate itself and an equivelant volume of liquid it's displacing (that it must displace to move forwards and replace behind it as it leaves).
As far as I know, isn't liquid incompressible? Gasses are compressible, so density changes with depth, but I think things like water have a constant density at all depths.
So Maybe you could set wether the big blue field is a fluid or solid, and if it's a fluid wether it's a liquid or a gas?
Pressure, on the other hand, does indeed vary with depth. Should we make an "implosion/explosion" threshold that bots explode/implode at if the pressure differential becomes too great?
Though I'm not so sure that's applicable since theoretically the bots' membranes are premeable to the fluid they're in.
I just think you are overcomplicating things ...
getting distracted by the details.
and that this has little if anything to do with simulating evolution.
yes ...
it would be nice to have it follow physical laws as much as possible ...
but that should be secondary ...
a lower prority than actually simulating how entities and their
environment evolve in a symbiotic relationship.
that's where the focus should be, imo.
we should get the basics of that working ... as they should ...
and provide a working platform from which others can continue
to explore and experiment.
and to simplify whenever possible, not complicate.
that's my opinion.
