Player migration

A discussion has been started at the Patchwide population system Pull Request. This PR, along with other things, touches upon the player migration logic. Currently when the player migrates to a new patch no population is transfered and the new patch has 0 population. Said PR moves 10% of the old patch to the new one as a proof-of-concept. There have been a few ideas, like

  • not transfering any population to the new patch but to penalize the player by removing some population off the old patch
  • transfering a fixed percentage
  • giving the player a small population boost in the new patch
  • not penalizing the player at all (keeping the current system)

hhyyrylainen had the idea:

For example on the patch map you could maybe select a source patch and a target patch to order your species to migrate. And you could do that even for patches you are far away from. That would give a similar level of control to the player that the auto-evo has regarding migrations

which gave me another idea: what if you can freely move around population in the editor like hhyyrylainen suggested AND you, as the player, can only go to paches already colonized. That way the player is not the first of its kind to visit the new patch.

What do you think?


Personally, I like the idea that the player plays a pioneering role in the game, such as how they and their species are the LUCA, and are likely to be the first to develop the nucleus, proceed into multicellular, etc.

That being said, the player having to participate in whichever patch they choose to migrate to would get in the way of migrating multiple populations to different biomes in one generation. This may not seem like too big of a deal now, but in the future when the patch map is much larger it may become quite the hassle.

I like the idea of allowing the player to push their populations around in a sort of command-like way because this also might prepare players for the strategic atmosphere that might arise in later stages when their species becomes more organized. In a way, this might make for a smoother transition into those stages by introducing strategic movement on a large scale so early.

So to put things simply; I believe that granting players the means to command their species to expand in the patch map in such a way could be a worthwhile feature. As for how to do so… I shall and various ideas on how we might do it.

Patch Movement:
I have two ideas on how the player’s means of migration might be limited.

  1. The player may only migrate species from one patch at a time. So if they have two inhabited patches they may move species from each of those patches and no more.

  2. They have a limited number of moves they can make, based on total population or some other factor (Propagation methods?).

I personally prefer 1.

Population Changes:
With the player’s species inhabiting multiple patches while only the player makes meaningful changes to their population, I believe that we could allow autoevo to effect the population of the player’s species when the player is not present in that patch. This way we could perhaps encourage finding a niche without a direct risk of a game-over for the player themselves.

I can understand if we may not be ready for autoevo to effect player population yet though.

Migration Cost:
I believe that 10% is a good place to start from. We can experimentally tweak it from there if needed. Though perhaps the number migrated could be controlled or effected in some manner?


I’m in favour of requiring the player to migrate first as well.

For the currently open PR (ie. the player moving to a new patch), I think this would be a good way:

  • No population moves along with the player. This means that if the player doesn’t survive in the new patch they get kicked out of that patch immediately and I think we should have some penalty for that, so the death population penalty should be applied to the patch the player migrated from. Otherwise it would be free to try migrating all over to find a good place without a strategy. Though, I think we should make this configurable in the code so that if we add like an easy mode, it could remove the population penalty in this case.
  • If the player manages to reproduce in the new patch, then that reproduction adds population for the player to the new patch.

The plan is that auto-evo will affect with like 80% strength all player populations. There’s been an open issue about that for years. It’s one of those features that’s been planned forever but no one has programmed it.

As I said above, I’d prefer to not have this approach, at least initially for the migrate feature.


I could see this backfiring. If we assume that, in the grand scheme of things, we’ll keep these kind of grand migration features, that might convey the idea that you’re playing as a god with control of an entire species, which to my understanding is definitely no longer true by the time you meet society stage.

On top of that, the RTS style stuff that I assume a future generation of Thrive devs will choose to implement at that time will probably feel entirely different from the turn-based, one-big-decision-at-a-time strategy gameplay of controlling 100 year migrations.

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I see this differently. I think there isn’t a reason not to allow the player to make multiple migrations at once. So the act of directing your population around in the microbe stage, would be very similar to commanding units in the later strategy phases of the game.

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It’s that or we just have your species migrate on their own before the player makes their choice which is worth considering, imo. It all comes down to how much agency we want the player to have over their whole species in earlier stages I suppose.

Personally I like the idea of directing migration for the reason I’ve stated above, it also let’s the player keep their species from trying to migrate to an unsuitable environment and die, thus potentially penalizing the player.

On the other hand, I like the idea of player species migrating on their own because it helps enforce the fact that the player is not in complete control of everything, and that just because you share the same species does not mean that you are necessarily allies. I assume we will have things such as rival competition in the future before we reach the civ stages afterall.

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