Starcraft 2 Analytics - Repor t 01 -
Tr u e Bui ldi ng costs an d oth er hi d d en costs i n SC2 The focus of this report naturally lies on the Terran race for two reasons: 1. Terran is the race which needs to invest the most into structures due to unit production mechanics and 2. Terran is the race with the highest hidden costs associated with structures. This makes it specifically for Terran players
important to understand such hidden costs and their implications. However, Zerg and Protoss are also affected by hidden structure costs. Hidden costs always come from lost potential mining time due to workers being economically idle for instance while traveling or constructing buildings.
The report starts with a discussion of hidden structure costs for each race followed by an analysis of a number of pro replays to get a feeling for the actual order of magnitude of the described effects. After that, you will find some typical examples for worker travel times which have their strongest impact on
economy during the early game. This is followed by a brief discussion of the influence of hidden structure costs on other aspects of the game such as supply efficiency or the supply cost of a 200/200 army. Finally, the role of mules is quantitatively described using the same pro replays as before.
Replay Analysis / Examples
Pro toss
TERRAN Effective Str uctu r e Cost = Str uctu r e cost + Lost mi ni ng Ti m e Terran structures do not only require an initial resource investment but also come with a cost over time as SCVs are economically idle while constructing buildings and traveling back and forth to the desired structure location.
The table below shows Terran building costs including income loss due to construction time. Typical worker travel times are given in the WTT box and are not included here as they depend on the specific structure location.
Several pro gamer replays have been analyzed to illustrate the role of (hidden) structure costs for each race in SC2. Terran was devided into bio and mech as it is most affected by (hidden) structure costs. Only replays of even games with standard openings that lasted longer than 40 min have been evaluated. Structure counts and travel times have been tracked through the replays until the 15:00 min mark.
Protoss is the race with the lowest additional structure costs. There are two hidden costs associated with Protoss structures.
Probe Travel Time The major hidden cost for Protoss structures comes from probe travel time when warping-in buildings. This typically adds 5-15 minerals to a single structure warp-in depending on location (see WTT box for examples). Travel time is significantly reduced (down to ~2 minerals per building) when warping in multiple structures at a time with one probe.
Replay Analysis I Investment into Structures at 5:00 min 2000 1500
Queens/OLs 1000
Minerals 500
Two time points are shown in the figures and tables of this section: A 5:00 min time point9 which represents an early phase of the infrastructure and a 15:00 min time point10 to reflect a solid well-developed infrastructure.
148 | 0
190 | 100
467 | 0
127 | 0
193 | 100
Please keep in mind that even though 15 min might seem a little too early to achieve a well developed infrastructure all replays represent even games so that no infrastructure was heavily damaged before the 15 min mark and the players were able to macro well during that time.
The Protoss building warp-in animation prolongs probe travel time. Probes need to stop in order to initiate building warp-ins which means they need to accelerate to normal speed again when returning. This effect is included in the worker travel time examples shown in the WTT box. WAPO slow down can be avoided using the mineral boost trick6. Furthermore, probes often collide with the warp-in animation and thus take a detour. A study of 100+ structure warp-ins including different building sizes showed an average probe delay of 1.4 sec (with a range of 13 sec). This delay translates into an additional cost of about 1 mineral per structure. Please note that WAPO time depends on building size (it is higher the large the building is).
Replay Analysis I - Investment Into Structures by Race
Terran (Bio)
Structures @5:00 min9
617 | 0
Protoss
Zerg
Cost (Min. | Gas)
1450 | 0
1425 | 175
1075 |
625 | 0
CT / WAPO / DM
263 | 0
250 | 0
7|0
200 | 0
Worker Travel Time
72 | 0
67 | 0
52 | 0
25 | 0
Total Hidden Costs
335 | 0
317 | 0
59 | 0
225 | 0
1785 | 0
1742 | 175
1134 | 0
850 | 0
Total Cost
Zerg
193 | 150
117 | 0
Terran (Mech)
(Q+OL: 600)
Replay Analysis II - Investment Into Structures by Race
15:00 min - Developed Infrastructure
142| 100
95 | 0
177 | 50
617 | 150
Zerg is the race which invests least into structures due to their superior unit production and supply mechanics. The main purpose of Zerg structures is to grant access to tech paths. This leads to a relative low number of structures compared to other races and thus to a relatively small (total) hidden structure cost.
Structures @15:00 min10
Terran (Bio)
Terran (Mech)
Protoss
Zerg
Cost (Min. | Gas)
5750 | 525
5925 | 950
5000 | 500
1875 | 400
CT / WAPO / DM
1138 | 0
1125 | 0
37 | 0
700 | 0
Worker Travel Time
273 | 0
292| 0
192 | 0
61 | 0
Total Hidden Costs
1411 | 0
1417 | 0
229 | 0
761 | 0
Total Cost
7161 | 525 7342 | 950 5229 | 500 2636 | 400 (Q+OL:1850)
Worker Travel Time
Discussion Early Gas. The earlier in the game the stronger hidden building costs affect Terran economy. For instance, the relatively high refinery cost of 95 minerals makes early gas a bigger investment for Terran players compared to other races.
Salvaging Bunkers. Only 75 minerals of the ~140 minerals (including SCV travel time) invested in a bunker will be refunded. This means Terran players lose in fact about 65 minerals (i.e. 46%) when salvaging typically positioned bunkers (and not only 25 minerals or 25%).
Scouting: Proxy Floating Racks vs. Early Scan. SCV travel time to proxy racks location: ~50 sec4 = 100 sec lost mining time = 67 minerals. Barracks building cost: 193 minerals. Total cost of a proxy racks: 260 minerals (with a total construction time of 2:45 min). Please note: A mule will mine 240-270 minerals5 over 90 sec. This means a proxy racks is on average slightly more expensive even though it requires more APM than scanning. However, the floating racks might be available longer for scouting and used to apply early pressure. Build costs of add-ons are not affected.
Supply Efficiency. Typical (total) supply depot costs vary between 125-130 minerals which makes Terran the least supply efficient race with a cost of ~16 minerals/supply (SCV travel time included, see WTT box).
Please note: a) There is in principle also the possibility to use gas mining workers to construct buildings which has not been considered here; b) an average SCV income of 2/3 minerals/ingame sec (i.e. 40 min per minute) was assumed1. Build times2 come from the same source.
Lost mining time due to worker travel time does affect Zerg but not as much as other races because (1) Zerg do not have to rely as strongly on buildings and (2) drones only travels one way due to morphing. This means minerals lost to worker travel time affects Zerg much less than other races (see box ‘Replay Analysis’).
Protoss
Zerg
9000 8000 7000 6000 5000 4000 3000 2000 1000 0
Queens/OLs
Gas Minerals Hidden Costs
Terran (Bio)
Terran (Bio)
Terran (Mech)
Replay Analysis II Investment into Structures at 15:00 min
5:00 min – Early Infrastructure
183 | 100
193 | 0
Hidden Costs
0
Warp-in Animation Probe Collision (WAPO) 120 | 0
Gas
Terran (Mech)
Protoss
Zerg
As discussed before, Terran players have to invest the most into infrastructure due to their inferior production mechanics. A fully developed Terran infrastructure binds about 2-3x as many resources as a comparable Zerg infrastructure. The most cost efficient opening (among standard openings) found was a Protoss 1-gate expand9. Protoss infrastructure also shows the least total hidden structure costs. Most of the gas mined during a game is invested into army development. Only a small percentage is used for structures.
Worker Travel Time (WTT) WTT depends strongly on the desired structure location. Please consider the examples given below as estimates to get a feeling for the order of magnitude of this type of hidden cost. All examples are focused on early game situations when WTT has the strongest impact on economy. WTT does not depend on the specific worker type as all workers have the same speed of 2.8125.
Structure Independent Supply Another structure related advantage of Zerg is that drones do not need to morph into buildings to increase the available supply count. Overlord production is entirely worker independent (but consumes one larva).
Economical damage due to WTT mainly affects Terran players for a number of reasons: 1. Overlords do not need to be constructed by drones, 2. drones morph into buildings (one way travel time only), 3. Zerg game mechanics do not require Zerg players to (heavily) invest into production buildings and 4. Protoss players can use a single probe to warp-in multiple buildings at a time to effectively reduce WTT per building.
Drone Loss due to Morphing (DM) Zerg drones morph into buildings. This mechanism seems drastic at first but it affects Zerg economy only in the early game in terms of lost potential income. Zerg players are able to mass-produce drones relatively soon in a game because they are not limited in worker production by the number of hatcheries like the other races. Therefore, drone morphing relatively quickly transforms into an additional cost of 1 larva and 50 minerals per building. This effect is (partially) compensated by lower Zerg structure costs (e.g. hatchery (300 minerals) versus nexus (400 minerals) or extractor (25 minerals) versus assimilator (75 minerals)).
Examples Travel to target location and back to mineral line 7,8 on standard maps4. Depot/pylon at ramp: Bunker (evolution chamber) at natural: Pylon at natural: Depot/pylon behind mineral line: Worker transfer main -> natural:
2x 8 sec 15 sec + 4 sec3 (15 sec) 2x 15 sec 2x 4 sec 16 sec
= 11 minerals = 13 minerals (10 minerals) = 20 minerals = 5 minerals = 11 minerals per transferred worker
Supply Efficiency True Worker Cost
Entropic Worker Cost
Hidden building costs also affect the resources needed to build up workers due to the necessary investment into supply.
True worker cost SCV Cost [minerals]: Probe Cost [minerals]: Drone Cost [minerals]:
50 + 120/8 (+5/8)* = 65 50 + 101/8 (+5/8)* = 62.6 50 + 100/8 (+1 Larva) = 62.5
(*numbers in parentheses include worker travel time)
(+0.625 = 65.63)* (+0.625 = 63.25)*
There is also an entropic worker cost due to worker production mechanics. Terran and Protoss worker production is limited by the number of available CCs/Nexi so that SCVs and probes are harder to replenish than drones. This increases their effective value11.
Supply Cost of a 200/200 Army Another way to think of the impact of hidden structure costs is by looking at the actual supply cost of a 200/200 army (assuming maxing out on 3 base for each race):
Supply Cost of a 200/200 Army 5000
Supply Depot: 120 minerals / 8 supply Pylon: 100 minerals / 8 supply Overlord: 100 minerals / 8 supply
4000
3000
Terran [minerals]: 200 supply = 3 x CC + 20.875 x SD = 3906 (4067)* Zerg [minerals]: 200 supply = 3 x Hatch(350) + 24.25 x OL = 3475 (3495)* Protoss [minerals]: 200 supply = 3 x Nexus + 21.25 x Pylon = 3325 (3439)* (*numbers in parentheses include worker travel time)
..or directly in terms of supply efficiency (see next section).
Main Supply Providers = 15 (16)* minerals / supply = 12.5 (13)* minerals / supply = 12.5 minerals / supply
2000
Structures
1000 0 Terran
Protoss
Hidden Costs
Zerg
Minerals
Command Center: Calldown: Nexus: (Hatchery:
467 minerals / 11 supply 255 minerals / 8 supply 400 minerals / 10 supply 350 minerals / 2 supply
= 42.5 (44)* minerals / supply = 32 minerals /supply = 40 (43)* minerals / supply = 175 (183)* minerals / supply)
(*numbers in parentheses include worker travel time)
Muling As demonstrated above, Terran infrastructure is most expensive for a number of reasons. To close the resulting resource gap Terran players need to use their extra source of income which is mule call-downs. A mule mines 255 minerals5 (on average) in 90 in-game seconds and uses up 50 energy (which is available every 89 secs12).
In the typical scenarios analyzed above, Terran players will have invested about 2-3k minerals more into their infrastructure than Zerg or Protoss players at the 15 min mark. Assuming the natural and third were taken at standard timings as in the replays above orbital commands will be available at 3:15, 6:30 and 12:30 min into the game which translates into 12 available mules13 until the 15 min mark assuming 4 scans up to this point.
This number of mules will have returned ~2550 minerals by the 15 min mark. Please note that 3 mules will still be mining at that time so that they didn’t return the full amount of minerals, yet. This example shows that mules are a necessity rather than a luxury for Terran players. Forcing Terrans to turn their third into a planetary fortress or to use scans excessively (e.g. to counter creep spread) will make them fall economically behind.
References and Footnotes [1] Liquipedia - Mining Minerals http://wiki.teamliquid.net/starcraft2/Mining_Minerals [2] Liquipedia - Buildings http://wiki.teamliquid.net/starcraft2/Buildings [3] Assuming the building SCV returns to mineral line at natural instead of going back to main. [4] This report is based on Starcraft 2 - Wings of Liberty v1.5.3 and the map pool of Season 5, 2012. [5] Liquipedia - Mule http://wiki.teamliquid.net/starcraft2/MULE [6] Liquipedia - Mineral Boosting Technique http://www.teamliquid.net/forum/viewmessage.php?topic_id=360509 [7] Travel times have been measured across the current 1v1 map pool and are in agreement with [8]. [8] Map distance and travel times by Orek http://www.teamliquid.net/forum/viewmessage.php?topic_id=324475
[9] Structures @5min. 1) Terran (bio): OC (2x) , SD (2x), barracks (3x), bunker; 2) Terran (mech): OC, CC, barracks, factory, refinery, SD (4x), tech lab, reactor; 3) Protoss: Nexus (2x), GW, CC, assimilator, pylon (3x); 4) Zerg: Hatchery (2x), extractor, spawning pool, spine crawler; Note: Cost of initial CC/nexus/hatch. not included in replay analysis. [10] Structures @15min : 1) Terran (bio): OC (3x), refinery (6x), SD (17x), engineering bay (2x), armory, baracks (7x), starport, factory, tech labs (3x), reactors (2x), ghost academy, bunker (2x); 2) Terran (mech): OC (3x), refinery (6x), SD (17x), engineering bay, armory (2x), bunker (1x), missile turrets (7x), baracks, factory (7x), starport, tech labs (4x), reactor; 3) Protoss : Nexus (3x), assimilator (6x), pylon (13x), templar archives, forge (2x), twilight council, photon canon (3x), robotics bay, cybernetics core, gateway (7x); 4) Zerg: Lair, Hatchery (2x), extractor (4x), spine crawler (3x), spawning pool, infestation pit, spire, roach warren, evolution chamber; [11] Entropic worker costs can be quantified by a statistical analysis, but are not included here to keep this first overview simple.
[12] Liquipedia - Energy http://wiki.teamliquid.net/starcraft2/Energy [13] Including mules available right when OCs finish.
This SC2 Analytics report was created by Finn. The purpose of these reports is to bring some order into my personal SC2 notes and most importantly to share them with the community. This is the first report and the most basic one mainly focusing on simple game mechanics. Contact Please send any information on typos, mistakes or simply your feedback to SC2Analytics@web.de with the respective subject. You can also follow SC2Analytics on twitter. Thank you! @SC2_Analytics