SWD mechanics
Morph ball control physics:
The physics rules for controlling Samus during morph ball are mostly the same both in the air and on the ground, with the acceleration (A) and max horizontal speed (M) constants being different. Other difference is that you lose control of grounded morph ball from frame 43 onward.
The precise rules for influencing horizontal character velocity (v) each frame with horizontal control stick position (x) goes as follows: Let i be the starting x-velocity, v the result velocity and x the control stick x-coordinate for the frame.
- If x = 0, then v = 0 (In other words, releasing the stick stops Samus immediately in place.)
- Else, v = i + A*x (Acceleration applied according to control stick position)
- Then after, if i*x >= 0 and |v| > M*|x|, v = M*x (If Samus holds the same direction she was moving beforehand, her speed will be capped by M*x)
During aerial morph ball, A = 0.275 and M = 0.712. On ground, A = 6.60 and M = 0.80
Why SWD exists:
SWD happens when you hold control stick against your moving direction for the frame 42 of grounded morph ball. Doing so makes you gain a ton of speed that frame, because the grounded acceleration is very high. If done any earlier than frame 42, Samus will slow down on the next frame according to operation (3), which limits her speed. However, when the speed burst occurs on frame 42, that won't happen as her speed can't be controlled anymore from frame 43 onward, and the speed limit is the effect of the control. Instead, Samus just slides in the "unmorph" animation, keeping her previous speed and slowing down a little due to traction.
On Goomyzoomy
The zoomy works because morph ball doesn't limit horizontal speed when you're holding stick against the moving direction (see 3.), and since the acceleration during aerial morph ball is quite low. The traditional zoomy method is:
- In morph ball near an edge on ground, hold slightly inward. This makes Samus move slowly inward.
- Smash stick the opposite direction. This creates the speed due to the crazy high grounded acceleration. You also need to be close enough to the edge to fall off on that same frame.
- On the very next frame, you must be holding inward again. If you successfully fell off and hold inward (opposite to the new direction you're now moving), you'll now decelerate slowly because of the aerial morph balls low acceleration.
This method is very hard to perform, as you need to be able to alternate control stick directions on consequent frames, which requires insanely quick control stick motion. However, I've found an alternative way which can be performed with more reasonable stick inputs:
Zoomland (zoomy with an "Buffered daughter dash" from landing)
Inputs for zoomland from "standing morphball" on an edge:
1. Down b on an edge.
2. Drift outward at the start.
3. Switch to inward drift so that it makes you land just by the edge, with speed inward.
4. Hold outward right before you land. You cannot afford even a single x deadzone frame.
5.Switch back to inward
precisely for the 2nd frame after landing. Continue holding in after.
To zoomland, you need to:
- Have speed toward the stage, opposite of the direction you want to fly toward, on the 1st grounded frame after landing.
- Hold control stick offstage, toward where you want fly to gain the speed.
- Be close enough to the edge to fall off immediately.
- Switch control stick to point back toward the stage again precisely the next frame, which is the 2nd frame after landing.
With zoomland, the aerial frames right before landing allow you to "buffer" the burst of speed ("daughter dash") Samus gets by inputting a direction opposite to her velocity in grounded morph ball. That works thanks to the low aerial acceleration: if you fall toward a surface with max horizontal speed, it'll take multiple frames for Samus to reverse the direction of her movement if she continuously holds back. Thus, from full speed inward, you can start holding the opposite direction a tiny moment before she lands, and then she daughter dashes on her 1st grounded frame after landing. Note that if there's even a single frame where your stick is in the horizontal deadzone before it reaches direction opposite to Samuses velocity, she stops immediately. That ruins the zoomland, as then Samus will start moving outward, and therefore she won't daughter dash after landing.
This zoomland method essentially replaces the requirement for very quick stick movement with a timing requirement (frame perfect), which makes it more similar with SWD. It's still obviously very difficult, as it requires an elaborate setup for good spacing and speed when Samus lands, in addition to getting the timing correct. From standing morph ball, the last shift in directions from outward to inward (the frame precise aspect) needs to happen from frame 38 to 39, which is 3 frames earlier than SWD smash input timing. You can also zoomland from other setups, like after running off of an edge. To succeed, you always need to have speed inward as you land, hold outward for the very first frame after landing and, and hold inward again after the 2nd frame.
