Bewarned this post is very long, technical and contains a bit of maths. I'll post a shorter summary below. 
* * * Introduction - safe to read
The crawlerless strategy is inferior in every way to a strategy involving crawlers, it exists as a challenge, and to hopefully make the game more enjoyable by reducing micromanagment.
For the terminally stupid, crawlerless strategy involves building no crawlers... there are less extreme variants like 'only use crawlers to rush SP's', or 'Only one crawler per base'.
The lack of crawlers hurts your game at two main points, the first is 'boot straping your industry with crawlers', using crawlers on forests to get to ~16 minerals per base, which allows very rapid construction of infrastructure and SP's.
The second is utilisation of terraforming, mainly Mines and Condensors which are somewhat less valuable when they have to be worked.
There are two terraforms which dont get an extreme benefit from being crawled, these are post-tree farm forests and boreholes.
* * * Getting into the heavy stuff
In analysis I will be using Factor Of Production, basically each Nutrient, Mineral or Energy is one FOP, in the early game minerals are more valuable than Energy, but later as you get energy enhancing facilities energy becomes more valuable than minerals.
Usuable FOP are Minerals and Energy, nutrients produce no real resource in themselves, but potentially allow harvesting of usable FOP. Net resources mean the resources after 2 nuts have been deducted for each worker.
Case study one:
Hybrid forests & +2 Econ.
forest = 3-2-3
Usuable FOP = 5
crawled:
Useable FOP = 3 (5 with engineers)
In this case, unless ineffeciency is high, you gain no benefit from crawling forests.. assuming you have population enough to work every tile.
Case study two:
Borehole & +2 Econ
6-0-7
Worked produces 13 FOP
Crawled produces 9 - 12 FOP
It is hard to get a net benefit from crawling boreholes - altough it can be worthwhile with a SSC and the amplification to energy...
* * * Cover your eyes and run away screaming
Terraforming Strategies.
Three obvious strategies come to mind, forest'n'forget, forest'n'forget + boreholes, Condensors + boreholes.
You can have highly productive bases once Hybrid forests arrive by working forests, boreholes, and any excess pop going to specialists. These bases compare well with a crawlered base, but do require the investment of a Hybrid forest... which is expensive, but well worth it.[list=1][*] 3 forests, hybrid forest, +2econ.
Each tile produces net resources of 1-2-3
the 3 tiles produce 3-6-9, and 1.5 specialists for another 4.5 - 7.5 resources.
Total FOP = 0-6-13.5 = 19.5 (Libarian/Techie/Thinker)
Total FOP = 0-6-16.5 = 22.5 (Engineeers)
Population = 4.5
[*] 2 Forests, 1 Borehole, Hybrid Forest, +2econ
The excess 1 nut from each forest feeds the borehole worker.
Total FOP = 0 - 10 - 13 = 23
Population = 3
Once engineers arrive you are barely better off working boreholes - may as well just go all forest and assign engineers.
[*] 2 Condensors (1flat, 1rolling), 1 Borehole, +2 econ.
Two Condensors produces net average resourcces 4-1-2, 2 nuts used on borehole, 2 left for specialist.
Total FOP = 0-7-12 = 19
Total FOP = 0-7-14 = 21 (Engineers)
Population = 4
Slightly less FOP than forests, but you dont need the expensive TF or HF to utilise. But requires a LOT more terraforming time. Quite a balanced tradeoff really.
[*] 2 Condensors, 2 soil enrichers, 1 borehole, +2econ.
Two condensors produce net average resources 8-1-2, 2 nuts used on borehole, 6 leftover for 3 specialists.
Total FOP = 0-7-18 = 25
Total FOP = 0-7-24 = 31 (Engineers)
Population = 6
This terraforming really blows forests out the water, so to speak.
[*] 3 Condensors (2 rolling, 1 flat), +2 econ
3 Condensors produce net average resource 6-2-3, nuts support 3 specialists.
Total FOP = 0-2-11 = 13
Total FOP = 0-2-17 = 19 (Engineers)
Population = 6
This is really quite poor compared to having a borehole... but it improves if you throw up some orbitals. The main downside is a low mineral output, so you wouldn't want all your terraforming like this.
[*] 3 Condensors (2 rolling, 1 flat), soil enrichers, +2 econ
3 Condensors produce net average resource 12-2-3, nuts support 6 specialists.
Total FOP = 0-2-21 = 23
Total FOP = 0-2-33 = 32 (Engineers)
Population = 9
Now were smoking, All condensors+enrichers produces the absolute most resources. And when you add in orbitals, weeeee.[/list=1]
If not +2econ : This has the effect of reducing every FOP rating by 3. In general specialists are more usfull if you dont have +2 Econ.
The significane of Population: Population is important when it comes to work out gain from orbitals. Total resources from orbitals, once all things have been accounted for:
mins, energy = Pop*2
# Specialists = Pop
Total FOP from orbitals, specialists
7*pop (Libies, Techies, Thinkies)
9*pop (Engineers)
10*pop (Tranies)
So population is really quite valuable when it comes to orbitals. Note those values are *maximum*, in reality you will get less.
Two important cases, Hybrid forest, condensors, All orbitals, Engineers.
3 forest:
FOP = 22.5 + 18 + 22.5 = 63
3 condensors+enrichers:
FOP = 32 + 36 + 45 = 113
We are talking approximately twice the resoures from a terraforming heavy scheme, however bear in mind that the actual difference will be a bit smaller, the smaller the base the less benefit from orbitals (this is because only 'whole' specialists benefit from an orbital, while in my calculations I have 'half specialists' and the like... dont ask me to explain further, because I just might
)
edit: Added formating, added explainations about +2econ, expanded on population...

* * * Introduction - safe to read

The crawlerless strategy is inferior in every way to a strategy involving crawlers, it exists as a challenge, and to hopefully make the game more enjoyable by reducing micromanagment.
For the terminally stupid, crawlerless strategy involves building no crawlers... there are less extreme variants like 'only use crawlers to rush SP's', or 'Only one crawler per base'.
The lack of crawlers hurts your game at two main points, the first is 'boot straping your industry with crawlers', using crawlers on forests to get to ~16 minerals per base, which allows very rapid construction of infrastructure and SP's.
The second is utilisation of terraforming, mainly Mines and Condensors which are somewhat less valuable when they have to be worked.
There are two terraforms which dont get an extreme benefit from being crawled, these are post-tree farm forests and boreholes.
* * * Getting into the heavy stuff
In analysis I will be using Factor Of Production, basically each Nutrient, Mineral or Energy is one FOP, in the early game minerals are more valuable than Energy, but later as you get energy enhancing facilities energy becomes more valuable than minerals.
Usuable FOP are Minerals and Energy, nutrients produce no real resource in themselves, but potentially allow harvesting of usable FOP. Net resources mean the resources after 2 nuts have been deducted for each worker.
Case study one:
Hybrid forests & +2 Econ.
forest = 3-2-3
Usuable FOP = 5
crawled:
Useable FOP = 3 (5 with engineers)
In this case, unless ineffeciency is high, you gain no benefit from crawling forests.. assuming you have population enough to work every tile.
Case study two:
Borehole & +2 Econ
6-0-7
Worked produces 13 FOP
Crawled produces 9 - 12 FOP
It is hard to get a net benefit from crawling boreholes - altough it can be worthwhile with a SSC and the amplification to energy...
* * * Cover your eyes and run away screaming
Terraforming Strategies.
Three obvious strategies come to mind, forest'n'forget, forest'n'forget + boreholes, Condensors + boreholes.
You can have highly productive bases once Hybrid forests arrive by working forests, boreholes, and any excess pop going to specialists. These bases compare well with a crawlered base, but do require the investment of a Hybrid forest... which is expensive, but well worth it.[list=1][*] 3 forests, hybrid forest, +2econ.
Each tile produces net resources of 1-2-3
the 3 tiles produce 3-6-9, and 1.5 specialists for another 4.5 - 7.5 resources.
Total FOP = 0-6-13.5 = 19.5 (Libarian/Techie/Thinker)
Total FOP = 0-6-16.5 = 22.5 (Engineeers)
Population = 4.5
[*] 2 Forests, 1 Borehole, Hybrid Forest, +2econ
The excess 1 nut from each forest feeds the borehole worker.
Total FOP = 0 - 10 - 13 = 23
Population = 3
Once engineers arrive you are barely better off working boreholes - may as well just go all forest and assign engineers.
[*] 2 Condensors (1flat, 1rolling), 1 Borehole, +2 econ.
Two Condensors produces net average resourcces 4-1-2, 2 nuts used on borehole, 2 left for specialist.
Total FOP = 0-7-12 = 19
Total FOP = 0-7-14 = 21 (Engineers)
Population = 4
Slightly less FOP than forests, but you dont need the expensive TF or HF to utilise. But requires a LOT more terraforming time. Quite a balanced tradeoff really.
[*] 2 Condensors, 2 soil enrichers, 1 borehole, +2econ.
Two condensors produce net average resources 8-1-2, 2 nuts used on borehole, 6 leftover for 3 specialists.
Total FOP = 0-7-18 = 25
Total FOP = 0-7-24 = 31 (Engineers)
Population = 6
This terraforming really blows forests out the water, so to speak.
[*] 3 Condensors (2 rolling, 1 flat), +2 econ
3 Condensors produce net average resource 6-2-3, nuts support 3 specialists.
Total FOP = 0-2-11 = 13
Total FOP = 0-2-17 = 19 (Engineers)
Population = 6
This is really quite poor compared to having a borehole... but it improves if you throw up some orbitals. The main downside is a low mineral output, so you wouldn't want all your terraforming like this.
[*] 3 Condensors (2 rolling, 1 flat), soil enrichers, +2 econ
3 Condensors produce net average resource 12-2-3, nuts support 6 specialists.
Total FOP = 0-2-21 = 23
Total FOP = 0-2-33 = 32 (Engineers)
Population = 9
Now were smoking, All condensors+enrichers produces the absolute most resources. And when you add in orbitals, weeeee.[/list=1]
If not +2econ : This has the effect of reducing every FOP rating by 3. In general specialists are more usfull if you dont have +2 Econ.
The significane of Population: Population is important when it comes to work out gain from orbitals. Total resources from orbitals, once all things have been accounted for:
mins, energy = Pop*2
# Specialists = Pop
Total FOP from orbitals, specialists
7*pop (Libies, Techies, Thinkies)
9*pop (Engineers)
10*pop (Tranies)
So population is really quite valuable when it comes to orbitals. Note those values are *maximum*, in reality you will get less.
Two important cases, Hybrid forest, condensors, All orbitals, Engineers.
3 forest:
FOP = 22.5 + 18 + 22.5 = 63
3 condensors+enrichers:
FOP = 32 + 36 + 45 = 113
We are talking approximately twice the resoures from a terraforming heavy scheme, however bear in mind that the actual difference will be a bit smaller, the smaller the base the less benefit from orbitals (this is because only 'whole' specialists benefit from an orbital, while in my calculations I have 'half specialists' and the like... dont ask me to explain further, because I just might

edit: Added formating, added explainations about +2econ, expanded on population...
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