StarCraft2: 2nd CC without expansion - is it worth?
Solution 1:
You are right. This thinking resulted in the fresh Griffith's 4OC Push against Zerg.
This exploits the following characteristics of the Terran race:
Terran has the most cost-efficient defence mechanisms of any race, which allows turtling.
Command center can lift-off - allowing safe construction without investing into defending an expo.
OC essentially pays back for itself after 2-3 MULE calldowns. Extra calldowns are "free-money".
Without going into too specific BOs or details, the goal of building OCs in this way is to:
Start from a basic BO to counter early pushes and then go for a transition.
Make you less dependent on supply depots, as CCs give you +11 supply.
Gain an economical advantage without the need of going for multiple expos.
Throw down a PF (OC if you can't) at an expo when your minerals are depleted or you need gas.
It does pay itself back fairly quick, but there is a timing window in which you are more vulnerable...
Scouting will help you determine if you can afford the OC or should do something else instead.
Furthermore, this thinking is slowly gaining attention amongst top players:
This was amazing. Boxer showed us some very quirky play, building twelve orbital commands throughout the game, outpacing Hyperdub in every way. Boxer had superior tank play, superior drops, and superior strategy.
Check this amazing game here.
This lead to the discovery of other late game advantages:
Dropping MULEs in the enemy army to cause him to friendly fire with Tanks/Colossus.
Instantly repairing Mechanical units on the field with MULEs.
Throwing multiple scans to quickly gain an omniscience advantage.
Solution 2:
It sounds like you are talking about something like this: post and post.
I've seen people use it successfully, but the problem you run into is that you have to burn a good number of minerals to start it up. 400 minerals doesn't sound like a lot, but its 8 marines or 4 marauders, which is a lot to be down.
In the higher ranks, the early/mid game pushes can be brutal. If you expand at your natural, you can start recouping your investment early, specially if you transfer half your svcs from your main right before it finishes. Remember, SVC mining rate doesn't increase linearly. 2 SVCS on two patches are better than 2 on one patch. 3 SVCs are better on two patches than one. With CC, you need to build your OC and THEN start dropping MUELS.
On a side note, i would say it makes sense to build your first expand inside your base and if you can't float it to your expand due to enemy pressure start teching it up right away.
Solution 3:
I had thought this terrible strategy was dead. I guess I was mistaken.
Ideas, such as: Mass OC, are largely the product of Theory Craft and generally fall apart during actual implementation. It's very easy to look at MULE harvesting rate and see the potential for abuse without looking at the opportunity cost or the RoI.
Let us assume we are sound business people and let's look at the Return on Investment for a single OC:
Buildtime CC: 100 secs 400 Minerals
+
Buildtime Orbital: 35 secs 150 Minerals
+
Lost SCV Mining time: 100*0.75=75 Minerals
-
Savings due to not building supply depots: 41.25 seconds+137.5 Minerals
-
Gained mining time due to not building supply depots: 41.25*0.75=31 Minerals
Total cost until you can use the OC: 93.5 seconds, 456 Minerals
Time until you start turning a profit:
On blue patches: Mules gather at a rate of 3 per second, so it takes a total of 245 seconds until you make a profit with extra OC builds.
If you have access to rich patches it gets better: Mules gather at 4.2 per second, so it takes only a total of 202 seconds until you turn a profit.
Let us compare that to the humble SCV:
If you have less than 2 SCVs per patch, investment in a SCV pays for itself after:
Building time: 17 seconds, 50 minerals
+
Cost for supply: 12.5 minerals, 3.75 seconds
+
Mining time needed to gather 62.5 minerals: 83 seconds
So a SCV at less than 2/patch saturation takes 103.75 seconds to pay for itself.
Citation: Teamliquid.net
When we look at the opportunity cost of the 4 minutes it takes for a MULE to pay for itself it almost immediately becomes apparent that it is not a worthwhile investment on its own.
This does not mean that MULEs are ineffective, or should not be used, however; if you consider the investment of the Command Center as part of the investment in a new expansion you are going to build and mine with SCVs then that cost is ammatorized across the SCVs and producing MULEs becomes cost effective. Since the upfront investment on a new Expansion is required regardless SCVs aren't a cost effective alternative. Once you have build the new Command Center at the Expansion SCVs once again become more cost effective than MULEs. This ultimately leads to: 1 Command Center per Expansion.
When coming across strange theory crafting like this, try to remember this guiding principle: If this is so game breaking, why isn't everyone doing it? The answer is almost never "they don't know yet."