Dropping is one of the most important techniques in the game, as it often allows you to circumvent choke points on the map where your opponent might be gathering his army. The two main applications of dropping are for harass and for actual army movement.
This article will lead you through the necessary Micro to use drops at maximum efficiency. For the sake of simplicity, the talk will be about "dropship" all the time, but the knowledge applies to all units, which can transport other units like:
- Warp Prism
- HotS: Overlords with Ventral Sacs for all Overlords
- LotV: Overlords with Ventral Sacs for a single Overlord
There are two basic techniques.
The first technique to drop a unit exactly where the dropship is at the moment, click on a unit in the wireframe of the dropship. This has the advantage of being able to select which unit comes out first. This will cause your dropship to drop the unit where it is, without decelerating.
Press D + Click
It is assumed your hotkey for unload is Grid (Hotkey Layout) it is ., which is standard. If you use
D-Clicking will send your dropship to 1) move to the specific point 2) stop there, and 3) start unloading the entire dropship. The order of unloading is from top to bottom and from left to right. So first, the unit at top left is unloaded, then bottom left, and so on.
These are more complicated, then the basic techniques.
Center of gravity technique
The center of gravity technique can be hard to pull off, but very effective when used correctly. One problem of doing the D-click method described above is using it with a larger number of dropships. When you click on some point, they will try to approach that point, drop all units in one spot, and stop there.
The center of gravity technique avoids this problem. When using this technique, the dropships will drop their cargo right where they are at the moment! As the name indicates, you have to click the weight-center of the formation. The center of gravity for two dropships, for example, is the point exactly between them. Though this can be very difficult to do on the fly, the result is a way better spread than you would usually get out of your drop. This method was popularized by Boxer. For more detailed information, see the Magic Boxes article.
To have your dropship unload its cargo while moving, and therefore spacing it, simply give it a move command, and then D-click on the dropship itself. To do this with a larger number of dropships, you have to repeat this technique for every single one of them.
This technique helps you hitting your opponent without being damaged. It's best used against opponents like Lurker, Broodlords, Disruptor and every enemy that shoots a projectile that takes time to reach its target. To perform this you also need a long range unit. For the execution you have to drop your unit, hit the enemy, and before the enemy hits your unit reload it inside your Dropship. This is often done with Tanks or Immortals.
It can also be used to effectively "increase" the hitpoints of the unit being loaded and unloaded. For example, if a small group of Hydralisks are fighting a Dropship full of Marines, the Dropship can both be used to cycle the Marines so that no one unit takes enough damage to be killed. If the Hydralisks focus on the Dropship, the Dropship can absorb damage and dance out of range to both allow the Marines to continue giving damage and avoid hits.
In this technique you want your opponent to think you are going to drop in his base. For example, sending a large number of overlords to your enemy's base will make him move his troops to defend against the drop, and hopefully, that opponent will reposition his mining workers, thereby effectively causing him to lose precious mining time. This can leave your opponent's expansions vulnerable to attack. However, it can also provoke an All-In response from your opponent.
This can also be used in PvP, where send a shuttle supposedly containing a reaver towards your opponents mineral line can cause him to scatter or force workers to a natural expansion mineral patch.