[Edited to take into account further observations based on comments from others, especially relating to native bonus]
First off, although this game has been out for 3 years, I've only been playing for a month, and it could be that someone has done this before. If so, I apologise for the repetition.
I'd been wondering how to tell what the maximum population of a planet would be and I think I've finally figured it out. Mostly. This guide concentrates mostly on the effect of planet size and quality on the population potential of a planet. If you're aware of other factors which affect maximum planet population, please let me know about them.
It seems logical that planet size affects maximum population and indeed it does. In fact, maximum planet population in Distant Worlds is proportional to the square of planet size.
Note that the maximum size for colonisable planets and moons is 40k.
Planet quality also affects planet size: in Distant Worlds, maximum planet population is proportional to the square of the planet quality.
Native Planet Bonus
Different races have different native planets. Your native planet is the one you start on. For example, for human empires, the native planet is continental; for Boskaran empires it is volcanic; and so on. Each race can achieve a higher population when it's on its own native planet type. Note that researching colonisation of other planet types does not, in itself, entitle you to the native planet bonus for the researched planet types.
The native planet bonus will add an extra 10% to the maximum population for the planet.
My testing has not conclusively established every circumstance in which you will get the native planet bonus. However, I think the following statements are correct, but it's possible people will find counter-examples:
1. Once a planet has been given the native planet bonus, it will keep it, even if the conditions which caused the planet to get the bonus no longer apply. (Edit: I have subsequently seen a counter-example, so I no longer have confidence that this is true)
2. The native planet bonus always applies to your starting planet.
3. If you colonise a planet which is a native planet for the race in your colony ship, you will get the bonus.
4. Any planets in your empire which have just one race on them will get the native planet bonus, provided that the planet is a native planet for that race. This applies even if the race on the planet is different from your empire's starting race.
5. If you have a mixture of races on a planet in your empire, and the planet is a native planet for at least one of those races, then you can get the bonus provided you have enough of the relevant race(s). There is an issue as to how much is "enough". My testing indicated around 45% of the total population is enough, but I can't say this is a hard and fast rule.
Putting it all together
So, assuming you don't get the native planet bonus, the formula for working out the maximum population of the planet is:
Max pop = 2.5x[(Planet Size/10000)^2]x[(Planet Quality/100)^2]
If you do get the native planet bonus, add 10% to the figure calculated from the above equation (i.e. multiply the figure by 1.1).
The max pop is in billions. Please be aware that planet size is given in thousands, which is why I have a divisor of 10000 in the formula. So if the game gives the planet size as 29.5k, then you have to use 29500 as the planet size in above formula.
For example, if you start the game on your native planet with a planet size of 29.5k and a planet quality of 100, your maximum population will be:
1.1x2.5x[(29500/10000)^2]x[(100/100)^2] = 23.93 billion
On the other hand, if you colonise a non-native planet with a planet size of 21k and a quality of just 65, your maximum population will be:
2.5x[(21000/10000)^2]x[(65/100)^2] = 4.66 billion.
So what's the theoretical maximum possible planet population? Well, assuming you're on a native planet, and that the maximum planet size is 400, and that the maximum planet quality is 100, the maximum population would be 44 billion.
NB: The planet quality and planet size displayed on the screen are rounded to two and three significant figures respectively. This means that the theoretical figures calculated by the formulas may not exactly match the figures you see, owing to rounding errors. For planet qualities down to 50, the theoretical figure should be within 2% of the actual maximum. For very low planet colonies (e.g. 5-20), the theoretical figure could be out by as much as 20% (but then, you wouldn't have much population anyway, to be honest!)
Edit - there also seems to be a minimum population: should you find yourself colonising a 0% quality planet, there will be a minimum population of 20 million.
I hope someone finds this useful.
- I'm a human not a Kiadian, so this analysis may contain mistakes. If you see any , let me know.
- I haven't looked into how this works when you start the game as a pirate empire, but I've no reason to believe it's any different.
< Message edited by Osito -- 4/30/2014 4:15:05 PM >