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#Post#: 1992--------------------------------------------------
Reaper jump exploit to scout the zerg main
By: guest99 Date: March 5, 2021, 1:37 pm
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Most of us in our early terran days have found our reapers
unexpectedly jumping to who knows where, and many of us have
also quickly realized that it has something to do with
shift-queueing a jump command. Last night I suddenly had the
idea to see if you can jump through the zerg main to scout it
(since it was patched to be unscannable in 4.7) by abusing this
bug. Thus, I spent some time trying to figure out the mechanics
of reaper jumping and eventually arrived at the conclusion that
yes, you can scout the zerg main, but the cost, likelihood of
success, and timings are quite a hurdle.
I have several mp4's linked via streamable to demonstrate
several points. I did my best to reduce file size while
maintaining clarity. Ideally they would just be text links
instead of embedding (or just small frame embedding), since the
video frame defaults to filling the entire window. Currently I
HTML simply have the https:// removed to stop automatic embedding.
Anyone know how to format this post better?
[hr]
Destination
Rule: Reapers jump as far as normally possible from (A) their
current location to (B) the clicked destination.
In this video (streamable.com/i0334h 5 MB), you can see that I
have several examples of a reaper moving along a straight line.
When I shift-queue the jump command, the command pane changes to
signify that the computer is waiting for me to input a
destination. The moment that I click on the ground, the computer
will draw a straight line from the reaper's current position to
the clicked position. It will calculate the jump using these
coordinates as if there were no shift-queueing shenanigans.
Thus, if I shift-queue a jump close to where the reaper is while
it is moving far away, it jumps a couple miles to do so. If I
shift-queue a jump close to where I expected the reaper to jump
from but is far from its actual position, it fails to do so.
Very helpfully, you can visually confirm what the reaper will do
by looking at the green path that SC2 normally gives for
queueing commands. The path for the final command fades away, so
you should queue a final move command in order to see it if you
need.
The cooldown on the jump command is 10 seconds. Thus, you can
queue two or more moon jumps in the following manner:
Method 1: Queue all your jumps before the reaper makes its
first jump.
Method 2: Queue your jump while the reaper is still airborne,
but after the 10 seconds cooldown has expired.
As expected, if the reaper lands before the jump cooldown is
finished, the reaper will cancel its queue (no "Cooldown is
active" error message or sound is given). See this video
(streamable.com/m2b9eu 3 MB).
I tried to use Method 2 to queue a jump across the zerg main and
then back into the main, but as it turns out, you cannot jump
into the zerg main from the outside. In this video
(streamable.com/i5vrze 2 MB), you can see that the reapers
simply cancel their queue order if you attempt to do so.
[hr]
Invincibility Frames
Rule: Reapers are untargetable for the first 3 seconds of their
jump.
When a reaper jumps, it actually cloaks (the light blue shimmer
is the visual effect) for a maximum of 3 seconds or until it
lands, whichever comes sooner. This is why you can evade a spine
crawler with a jump. After the cloaking falls, reapers are
effectively treated as colossi. This means that roaches, spines,
and even drones can hit airborne reapers. However, nothing can
block the reapers from moving along their flight trajectory, and
the reapers themselves do not push other units out of the way.
Unfortunately, large spines still do splash damage against
airborne reapers. Most melee units can hit airborne reapers but
it is not guaranteed, especially for the slow attacking/rotating
bruta. The reaper explosion trail follows the flight trajectory,
which is funny to see but has been noted before in general SC2
physics. See this video (streamable.com/acqyub 11 MB) for all
melee zerg units (now that I think about it, I bet that spores
can kill airborne reapers).
As an aside, this also means under normal circumstances that a
reaper should get at least one shot off on its target after it
lands, but there is one general exception. If the reaper lands
on top of a zerg unit/structure, the reaper will "bounce" off
and end up facing the wrong way, which costs a few extra frames
to turn around and shoot. Under these circumstances, some units,
such as ultras and more importantly, large spines, can sometimes
kill the reaper before the reaper can shoot. In more practical
terms, you risk losses if you jump your reapers on top of a
large spine instead of right in front of it.
[hr]
Practicality
In order to jump across the main, you have to traverse a little
more than 180 degrees around the perimeter of the map (longer if
it takes too much time for you to queue all the move actions).
This is easiest to do at the beginning of the game when terran
walls are not complete and zerg forces have little map coverage.
This also means that all you will see is whether or not the zerg
spent their first supply on extractors or not... if you're
lucky. If a zerg even does put four extractors in the main,
what's the likelihood that your reaper's trajectory will find
them? Instead, it might be better to use this jumping trick to
check if the zerg upgraded capacity or not, which you could do
more simply by just walking in like a normal person.
Additionally, you probably can't afford to sacrifice many
reapers, and you need at least two spaced reapers to jump
starting from as close as possible to the mid-side for the
fewest reaper deaths... which is where most zergs do not put
their first extractors (see this video (streamable.com/jdiqju 2
MB) for a success and this video (streamable.com/cwuqny 15 MB)
for multiple fails). EDIT: actually, a reaper's vision covers an
impressive amount of the zerg main and will likely see a few of
a zerg's first placed extractors.
Towards the mid-game, reaper jumping can also be safe-ish if a
terran eliminated one of their large spines, and if you're
lucky, someone ioned the spines in the main on the same side. In
this case, a reaper can jump diagonally across the map (avoiding
melee units hopefully), which also is more likely to find the
zerg extractors for the reason mentioned above. However at this
point, you can usually tell whether the zerg has a lot of eco or
not without an explicit scout. Instead, you might use this trick
to see when brutas pop out or if you're about to engage the ramp
and you don't know if the zerg is hiding a spine/hydra wall at
the top (I usually just send 2 elites in split apart). EDIT:
however, the massive number of unit spawns makes it really
difficult.
Regardless of the benefits of scouting at such-and-such timing,
it's also difficult for the reapers to get around the map in the
first place. If you misclick a waypoint into a lake or onto a
wall, the reapers may derp around a lot and end up getting
separated from each other. This is nice for avoiding the splash
damage from a large spine, but it also means the zerg can get
more shots off.
Nevertheless, the jumping reaper should technically provide
vision into the main. Maybe you can warp in an italis or
something? I'll be trying to do this today to confirm that
reapers can see the main when the game has real fog enabled.
EDIT: and here it is!
[hr]
HTML https://streamable.com/1szcur
[hr]
Today I also found that you can use the reaper scout to provide
more consistent high ground vision as you engage up the ramp
into the main: (streamable.com/esj5l7 4 MB). That being said,
it's probably easier to just have a marine or two on move
command to do the same thing.
And now, an honorable mention to Ace who sent about 150 reapers
for a victory flight over the zerg base (streamable.com/wnxcwj 8
MB). At the end of this video, it's also apparent that the
reapers drop unnaturally to the ground after the flight, and
their idle animations get sort of stuck in flight mode.
#Post#: 1996--------------------------------------------------
Re: Reaper jump exploit to scout the zerg main
By: deorai037 Date: March 6, 2021, 5:42 am
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Not gonna lie, this is honestly amazing (and hilarious) to
watch. Kudos to you
#Post#: 2055--------------------------------------------------
Re: Reaper jump exploit to scout the zerg main
By: SpaceBalls Date: April 7, 2021, 10:47 am
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Is this a bug or a feature?
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