When to build farms & markets?

Well the economic buildings only benefit you if you pull the slider toward wealth just like the other 2 options. You have to put some production into wealth to get anything from those buildings. They are a % bonus just like manufacturing and research.

Yes, I understand that aspect. My point was that I was never forced to put part of my slider into wealth until the end of the game. I was wondering when it was useful to utilize these buildings in general.

Farms give you more population, and population gives you more Production (which increases Manufacturing, Research, and Gold all at once), as well as makes the planet harder to conquer.

If you're playing on a small map, you'll never reach a point where you NEED economic buildings, because the game is over in 30 minutes, but if you start playing on a Gigantic map or above, the game might last days or weeks, which means you actually will need to set aside some planets to generate income to pay for everything. To accommodate that, you'll need to do several things differently:

1) Start specializing planets. This means you'll need planets with their individual sliders set to 100% Production, Research, or Income, rather than using the Empire-wide slider for everything.

2) Start setting aside space for Farms and a Hospital on high-class planets. This will allow their output to continue to increase well into the late game. Don't forget to increase Morale in anticipation of higher population. You do this on high-class planets only because low-class planets don't have any space for farms.

3) Look for planets with increased Tourism output, and build a Port of Call there. Tourism income is unaffected by Wealth buildings and the Wealth slider, so you can do this even on 100% Manufacturing planets.

4) Use a planet's geography as a cue to what specialization would fit it best.

Naturally, if you never play maps larger than Small, you'll usually end your game fast enough that it doesn't matter. The longer a game takes, though, the more complex it gets.

Oh, i understand. Well the way you put it as 'forced' makes me wonder. It took me a bit to get when the best time to start producing wealth in GC2 was optimal to prevent bankruptcy and of course that varied on race traits and choices. So, I don't really have an answer for you at this point, things have changed so much in the past few builds.

Good info. Is there anyway to see how population is affecting manufacturing on the planet screen? I see a Raw Manufacturing value, and I'm guessing population comes in here, but I don't see any indication of the exact bonus. I'm assuming that under the right conditions, building a farm could result in more overall manufacturing than building another factory, although we'd have to know the exact equations in play to determine that break point. Is there any rule of thumb in this regard?

The sum of your raw manufacturing, raw research, and raw wealth production is your raw production. Population adds a bonus to raw production which may be computed as

2 * (population)^0.7

This bonus adds to any flat production bonuses you have (there's a +5 from the colony capital, the homeworld gets another +5, there's a tech for +1, and I think there's a few other things, like an improvement or two, which add flat production to your planet). Thus, a world with a population of 10 will receive about 10 production from its population. There are also a few things which give percentage modifiers to production (approval and economic rings, mostly), which multiply the base production (i.e. the sum of the flat production bonuses and your population-based production).

Production is then distributed out over the three output types based upon your wheel settings to generate the raw (output type) numbers, which are then multiplied by the sum of the bonuses to that output type to produce your gross (output type) numbers.

So yes, if you want to see your production, you can set your sliders to 100% of some output type and then look at the raw (output type); that will be your world's production. There isn't an easier way to look at this at this point in time.

We do know the equations:

[Production] = (1 + [approval mod] + [production bonuses]) * ([flat production] + 2 * [population]^0.7)

[Manufacturing] = [manufacturing fraction] * [Production] * (1 + [manufacturing bonuses])

[Research] = [research fraction] * [Production] * (1 + [research bonuses])

[Net Wealth] = [wealth fraction] * [Production] * (1 + [wealth bonuses]) + [tourism] - [maintenance]

[tourism] and [maintenance] are not based on production. I'm not certain if a planet's population has an effect on tourism; the only two things I know about tourism are that there's a number in GalCiv3GlobalDefs called GalacticTourismSpendingMod which is set to 0.25 by default, and that there are buildings which modify it.

It will therefore be beneficial to build a farm if

[production with farm] * [old multiplier] > [production without farm] * [new multiplier]

or alternatively

[production with farm] / [production without farm] > [new multiplier] / [old multiplier]

where [production with farm] is the production you would have with the farm and [old multiplier] is the overall output multiplier you currently have, while [production without farm] is the production you currently have and [new multiplier] is the overall output multiplier you will have if you build (some kind of output multiplier building) in place of the farm(s) and approval building(s) you're considering adding. Note that you need to include the approval multiplier in the overall output multiplier or in the production numbers (pick one; don't include it in both), and that adding farms will generally (though not always) result in you wanting to add approval structures since the approval modifier stacks multiplicatively with the output multipliers, which can make it a fairly severe penalty (the approval modifier ranges from -25% at 0% approval to +25% at 100% approval and follows a curve defined by several points in GalCiv3GlobalDefs; open the file with a text editor or a web browser or some other program that can read the file and search for 'approvaltoproductioncurve' if you want to see what the points are, but it's approximately the cubic function f(x) = x^3 + 0.25*x + 1, where x = [approval] / 100% - 0.5, though I think the game actually uses a linear interpolation between the points listed in the XML file).

If you know the values, then you can use this formula to compute the value of [old multiplier] where it becomes better to add a farm than a new building (or buildings, if you include the approval structure you probably will need to add with the new farm):

b = ((B + 2 * P^0.7) * (1 + a) / (B + 2 * (P + f)^0.7) - 1) / (1 - (B + 2 * P^0.7) / (B + 2 * (P + f)^0.7))

where b is the bonus for the old multiplier ([old multiplier] = 1 + b; b*100% is the number reported in the output tool tip, though if you're using a world to obtain multiple production types you're going to have to compute the weighted average of the bonuses rather than just looking at the bonus to one output type), B is your flat production, P is your maximum population without the new farm, f is the bonus to maximum population you get by adding the farm, and a is the bonus you can add to your output multiplier by adding new output structures rather than the farm and any associated approval structures to maintain a constant approval rating.

For a planet with a base maximum population of 5 and a flat production bonus of 5, if a farm gives +2 maximum population and each output structure gives +0.25 to the output multiplier (+25%, e.g. a basic factory with no levels), then you will want to add farms when the output multiplier is +70%, and again when the output bonus is +113%, and again when the bonus is +155%. However, be aware that these were computed ignoring approval effects, which means you traded one farm for one factory (or other appropriate structure and vice versa), which is inadvisable.

As you can see above, there's a lot of math involved, but think of it like this: population adds to your base production. Base production is nice, but only because your other buildings magnify base production so much. So, on a low-class planet with 4 tiles to improve, you can't build many other buildings, certainly not the ones you need to sustain a large population, so putting a farm on these planets is a waste unless your goal is to set it to 33/33/33 and then let it coast along as a master of none. However, on a high-class planet, you have more room to build things, which means much larger modifiers.

So, on a high-class planet with lots of room to build stuff, and lots of adjacency, you're going to want some farms. Not that many, though, maybe one or two. I'd put three at the most, because you have to keep approval up to get the most out of it, and that takes space as well unless you're using Economic Starbases with approval mods.

A pretty good rule of thumb is that you dedicate about 50% of a world on supportive infrastructure such as morale, population and industry and the other 50% for either wealth or research, not both at the same time. Or on industry worlds about 2/3 industry and 1/3 supportive infrastructure.

Juts to give you a rough estimation on a good balance.