Here is an example of how basing our editor around solving problems posed by constraints can lead to some really engaging editor gameplay, with a reduced need of just adding an endless number of tools for the player to interact with.
Center of Mass
Relevant information from prior post if refreshment is needed:
Marine animals with a center of mass closer to their front (sharks, crocodiles, rays):
- Have stronger limbs in the front, optimizing striking and lunging capabilities.
- Find it easier to swim downwards, being generally better optimized to diving.
- Spend less energy swimming since they are better able to “cruise”, reducing movement costs.
- Are generally less nimble and agile.
- Have more prominent fins in the front to help balance movement.
- Are better able to stay attached to the ocean floor.
Marine animals with a center of mass closer to their rear (tuna, sailfish, flying fish):
- Have stronger limbs in the rear, optimizing movement and explosiveness in movement.
- Find it easier to swim upwards, being generally more buoyant in propulsion.
- Spend more energy stabilizing orientation, thus increasing movement costs.
- Are generally more nimble and agile.
- Have more prominent fins in the rear to help stabilize.
- Are better able to breach the water surface, escaping predators.
Center of “gravity” is used more often in biomechanic circles. I’m choosing to name this factor as center of mass in order to more clearly associate it with mass itself. The center of mass in an organism is really important in determining biomechanics and gait, as well as the arrangement of a body plan.
Tools Derived from Center of Mass
Mobility Appendages Proximity to Center of Mass
In marine animals, fins closer to the center of mass often help with agility and thrust at the cost of some stability, while fins farther from the center of mass often help with stability at the cost of some leverage.
For now, I’m going to say that stability can be a stand in for a measure of ATP costs associated with movement. Learning from this, we can say that:
- The closer to the center of gravity an appendage is, the more it benefits mobility at the cost of greater ATP cost. The farther it is, the more energy efficient the limb is at the cost of some mobility.
Note that the effects of a limb are additive as long as it doesn’t negatively impact your streamline measure too much. When I say “more efficient at the cost of some speed,” I don’t mean the speed of your organism goes down, I mean the limb’s speed bonus isn’t as fast as it could be.
Below are examples of fish with the same center of gravity, pretty far behind their heads. The top fish really emphasizes stability at the cost of maximum speed, while the bottom fish really emphasizes speed at the cost of some stability. As a result, the first fish is generally better suited for distance and efficient cruising, while the second fish is generally better suited for quick movement in bursts as opposed to efficiency.
Note that in actuality, stability does have an important impact on speed. So perhaps another interpretation of stability could be as a sort of coefficient to speed as well as energy, but that could be complicated to manage.
Mass-Bearing Features & Appendages
“Heavier” parts of the organism will shift the animal’s center of gravity more or less dorsally or posteriorly. An example of an aquatic organism with a high-mass section of their body is Dunkleosteus, which notably has a heavily-armored skull, shifting the center of mass forwards:
This suits its ecological role very well; an animal that was likely built for inflicting a ton of damage on armored organisms, having a forward-set center of mass really helps it to hit like a freight train. Note the strong pectoral fins, providing control to the center of gravity, and the prominent, backwards shifted tail and dorsal fin, providing greater stability.
Varying Torso Size
Animals that have segments of their body enlarged tend to have their center of gravity shift that way. In Thrive, making a segment of your torso wider can shift the center of mass in a responsive way.
Varying Torso Length
Lengthening the torso, creating a sort of “tail”, is a common strategy utilized by many animals to shift their center of gravity backwards. Representing this mechanic in Thrive can implicitly lead to similar phenomena occurring organically in Thrive.
Here, from representing a dynamic constraint, we give ourselves a framework to understanding what kind of tools could be useful in an engaging editor, and can set up these tools to result in gameplay experiences which can seriously reflect a lot of the pressures real life organisms face in a very interesting way.
I can easily imagine such a system resulting in fun personal goals for the player to achieve: build the fastest animal by shifting the center of gravity backwards, shift the center of gravity as much as you can forward and try to build an animal able to succeed with that sort of pressure, etc. It also leads to many interesting “stories” behind the body plan of an animal. Why does this clade have very prominent fins in the back? Because its ancestor was really front-heavy, or it wanted to maximize speed.
There is only so much of “finetune this mouth/leg/eye/hand" etc. we can provide to the player without it being micro-managey to the player, or without us turning development of the macroscopic stage into “how many additional things can we fit here”. Having these significant and clear constraints can naturally result in the sort of dynamism players face, without throwing their attention to 5 different things on their creature that they must adjust sliders on or shape differently in an editor trip.
I am starting to think that this is an ideal way of creating an engaging editor, and think that nailing down the macroscopic factors, parameters, mechanics, etc. dealt with in the editor will make conceptualizing it a lot easier. There are some things we need to be wary of, however:
- There should be very little actual “restriction” placed on the player surrounding these mechanics; that is, instances where the editor flat out says “you can’t do that, and we won’t let you leave the editor until you fix it” should be as absent as possible surrounding these constraints. Even if there are only three or four of these larger constraints, situations where the player has an organism with multiple issues can emerge, and this can easily lead to confusion and frustration.
- Information and UI elements surrounding these systems should be clear as to the statistical impact of your choices. Bonuses should be highlighted and minuses should be pointed out, and you should be able to see what your surface area, mass, where your center of gravity is, etc.
- There should be ways for the player to alleviate the pressure of some of these constraints if they wish, so as to create some sort of accessibility. This can be done in a way that doesn’t harm the depth of Thrive, as long as the bonuses of these constraints are also nullified to the same extent the negatives are. It can also be done in ways that are scientifically accurate: animals with less mass don’t have to worry about their center of gravity as much, and the presence of a swim bladder in some fish helps to alleviate the buoyancy effects of their center of gravity.
- It should be clear to the player when a certain constraint is more important to their organism. Animals with a certain type of skin will need to look at their surface area a bit more, while animals with another type of skin will be less affected. Smaller animals won’t have to worry about their center of gravity as much, but larger ones should. This will also reflect progression: early, primitive animals often had to focus a lot more on surface area, as an example, then different strategies related to integuments reduced this pressure.
- It’s better to have three well-designed, intuitive, and engaging constraints which are interrelated than it is to have a hundred constraints, addressing the tiniest of details.