When the microbe stage ends the oceanic multicellular begins. In this stage the player will design an aquatic organism and then swim around an ocean. This raises the following questions;
- What is the top speed of your organism? This is important in predation.
- What is the energy efficiency of your locomotion?
How the player will design their organism is not completely fixed however there are clearly going to be some important factors. The organism might be skinned using something similar to the microbe stage cell membrane algorithm and so we need some way of determining drag from the shape with a minimum of computation (because there will be many species to do this calculation for). This is complicated because the fluid dynamics has two different regimes, a low Reynolds number regime where the flow is largely laminar and a high Reynolds number regime where the flow becomes turbulent, creating a wake and greatly increasing the drag.
It is possible there will be different types of muscle which can be connected in different places to different skeletons so we need a way of calculating the force the fish can produce and the energy consumed in producing such a force.
Moreover there may be many different types of locomotion to be considered, as described on this page, https://en.wikipedia.org/wiki/Aquatic_locomotion and we need to determine if there are more which we would like to include because they are physically possible but not seen on earth.
Overall we will need to settle on a model which suits our usual needs; that it uses reasonable computation, that it is reasonably scientifically accurate and, most importantly, that interacting with the model gives deep and compelling gameplay.
So far I have made no progress on these problems but these are a couple of interesting sources:
This review is very interesting and points the way to a lot of sources which might help.
This paper raises the additional complication that swimming in a shoal may be more efficient than swimming alone, so we may wish to take that into account.