I have a question about optimizing vertical acceleration, specifically with Peach and other DJC characters. I think that this question will hold for those with regular jumps as well. Sorry if I explain it poorly, let me know if I should clarify it further.
We know if Peach wants to get up to a certain height as fast as possible, she has to cancel her rising full hop with the second jump BEFORE it reaches its apex. At some point the vertical acceleration of her first jump decreases to some low enough non-zero value at which it time is best to input the second jump. This keeps her from wasting time in the 'slower' rising state and get the the DJ 'dip' over with, so that she can resume the upward trajectory with a renewed upward acceleration.
Lets say we're in a Sheik edgeguard situation with Peach on FD. I hold ledge, Sheik up+b's to the stage, I get up and down tilt. Sheik is sent upward with considerable stun (assume no DI). Now the goal is for Peach to get up to Sheik as fast as possible and reverse nair (or uair depending on %), usually at the zenith of Sheik's arc.
There is certaintly a 'feel' to the timing, but I was curious if there were specific jump input frame intervals for each character that would make them reach the a certain height as quickly as possible. This interval would change with the specific height and if there was any horizontal component of course. Maybe as a general rule of thumb we can do stage level to top platform of battlefield, or the highest possible point reachable in X frames for each character
Another character I can think of that uses a quick double jump to cover vertical distance fast is Ganon, when wanting to get onto a platform to waveland. I think this is only faster on certain stages due to platform height (can someone confirm?)
Yeah you could calculate this quite easily with any character without special doublejumps. It becomes more difficult, but far from impossible, to calculate this for Peach and other special dj-ers. This is because they have set velocities on each frame of their doublejump, and when you perform an aerial it takes the velocity of the dj frame before you aerial and then subtracts fallspeed from that point onwards.
I can't think of an equation that will simply give you the correct answer (but maths is a huge subject, there probably is a way im forgetting). But that's not that much of a problem because we have computers, and calculating something 50 times and finding the lowest number will take no time at all.
I general idea would be:
v = fullhop velocity
f = fallspeed
d = dj velocity
t = total distance
Sum[ v - nf , { n, 0, x } ] + Sum[ d - nf , { n, 0, y } ] >= t
Have the computer try like 50 or so pairs of x and y, then sort through all the results for the lowest x value.
Doing this for special DJers will be like
d
n = dj frame n velocity
Sum[ v - nf , { n, 0, x } ] + Sum[ d
n , { n, 1, y } ] >= t
and you would have to write down all the velocities on each frame to feed the equation. This doesnt take into account how the velocity changes when you aerial, but wouldn't be too hard to do, you would just need to specify for how many frames you want that velocity to be calculated.
edit: at first i didnt think this would be that useful, as good players just have a feel for it, but it would be kinda cool if it was displayed on a visual graph with multiple total distances, creating a nice gradient. Im thinking like a screenshot of whatever character on whatever stage, with a rainbow line showing his fullhop height, then another rainbow line above showing all the possible heights from a doublejump, and each colour of the line matching the fullhop height with the fastest possible way to get to that dj height.
I will definitely put this on my to-do list, but I have some other big projects I want to finish first.
Also, it becomes more complicated when you want to waveland on a platform or something, as the ECB becomes locked to the Base Position Star for 9 frames after doublejumping (and fullhopping). That and the fact the ECB even exists, as the position calculated with above equations will be from the BPS. So you would have to know the ECB pattern of the fullhop and doublejump, which thankfully can be found easily, but it increases the workload by quite a lot.