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In Starcraft 2 Marines can stutter step, meaning they attack move and start their attack animation, this is canceled by a move command and then attack move again.

Theoretically there should be a sweet spot. With the optimal frequency the marine does the same damage as a standing marine, but moves the farthest possible.

Here is my question: What is this frequency? How often should I stutter step per minute and how long is the input delay between A + left click .... left click .... A + left click.

If I wait too long between A + left click and left click the animation is canceled too slow and my marine does not move that far. If I wait too long between left click and A + left click my marine does not shoot ASAP.

As a bonus I would like to know what APM I would need to perform this optimal stutter step.

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Typically a stutter step is done with the stop command. I.E. Right Click, "S", Right Click, "S". I could only imagine the horror of A+ Left Click. –  Nick122 May 17 '12 at 19:42
Create a question for this and I will answer it :) There are pros and cons for every method. –  ayckoster May 17 '12 at 19:46
Done. gaming.stackexchange.com/questions/67620/… –  Nick122 May 18 '12 at 13:51
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2 Answers

Marines have an attack cooldown of 0.8608 seconds, (-0.28693 while stimmed).

Note that you should be stutter stepping with right click and the Stop of Hold Position hotkey. There will be a small lag-dependent delay between pressing S or H and your Marines opening fire, which you will have to experiment to find for yourself. You can right click to move as soon as the attack animation starts, as Marines deal damage instantaneously.

Perfect stutter step micro consists of pressing S or H every 0.8608 seconds (or 0.57387 seconds stimmed), and right clicking as soon as your Marines open fire.

EDIT: If you attack move while the Marines are on cooldown, the Marines in range of an enemy will not move.

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This answer is not quite correct because it doesn't account for turn speed. This is the correct answer when attacking a unit you're moving towards, however. –  Decency May 17 '12 at 1:20
Turn speed has no effect on cooldown though, right? It would only affect the delay between stopping and moving again, which is also dependent on lag. Please correct me if I'm wrong. –  Ampersand May 17 '12 at 1:23
Still not the correct answer. I looked into it and there seems to be a random delay between attacks (Random Delay Maximum 0.125 Random Delay Minimum - 0.0625) see teamliquid.net/forum/viewmessage.php?topic_id=127158. Furthermore you forgot to factor in the game speed (1.4 X). I tried to set a metronome to 60/0.8608 = 69 speed and it was all wrong. But you are right that its easier to stutter step with stop or hold. –  ayckoster May 17 '12 at 1:56
+1 for your help, but I posted an answer myself. –  ayckoster May 17 '12 at 2:18
Hi, I think you're right actually. Turn speed shouldn't affect the interval, just when you need to begin each attack. –  Decency May 17 '12 at 3:51
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up vote 3 down vote accepted

Here is what I found (thanks to Ampersand for the hint)

  • base Attack speed = 0.8608 seconds
  • while stimmed = 0.57387
  • game speed factor is about 1.4X
  • random delay between attacks (all units): between 0.125 and - 0.0625

Considering the worst case with the longest random delay but not considering turning speed this leaves us at:

  • worst case unstimmed = 0.8608 + 0.125 = 0.9858
  • worst case stimmed = 0.57387 + 0.125 = 0.69887
  • considering game speed factor 1.4
  • worst case unstimmed ingame = 0.9858 / 1.4 = 0.7041
  • worst case stimmed ingame = 0.69887 / 1.4 = 0.4992

Calculating hits per minute would be:

  • worst case unstimmed per minute = 60 / 0.7041 = 85.21
  • worst case stimmed per minute = 60 / 0.4992 = 120.19

I checked also for the stutter step method, there are 4 and each depends on preferences:

  • stop
  • hold position
  • attack move
  • patrol

Depending on which you use this would translate into the following APM:

  • stop, hold position: 2 * 85 = 170 APM and 2 * 120 = 240 APM
  • patrol, attack move: 3 * 85 = 255 APM and 3 * 120 = 360 APM

In any case there is a small delay you have to wait until you move after you fire. I could not find any reliable value for this time, you just need to "wait" until the marine fires.

Here are the sources I used:

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I'd upvote... but i.imgur.com/1z5aQ.jpg –  Ampersand May 17 '12 at 3:00
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