I just can't wrap my head around the purpose of this and similar abilities.
Acrobatics clearly states that you are limited to just your movement speed in any given round for distance allowed in a jump.
So rarely are you above 30ft and for most your likely 20ft because of armor.
Yet there are a number of abilities that give you big bonuses to this skill check. If your dex heavy, 3 or 4 levels in with a dip in Kineticist with Air Focus... You can meet 20 to 30 ft in a jump without spending much.
So I'm not sure entirely the point beyond early level use. Is that maybe the intent?
The Ninja, the Kineticist, and I'm sure there are some spells for it. But beyond dipping a little and going purely monk because of the increases in movement speed... why would you? Is there maybe a feat or something out there that bypasses the limit on it? Or are these abilities just so you don't have to bother putting points into the skill? I assume I answered it for myself there. As just an option for people wanting to allocate points elsewhere? Or... am I just misunderstanding the ability all together?
So, you need to succeed a DC40 check to make a 10 foot vertical leap. If we assume that movement speed vertically is halved just like for flight, then 15ft vertically or a DC60 acrobatics check is the max most characters can achieve.
Monks are different however in that they can achieve a movement speed of 90ft normally at high level, and up to 120ft with the Sudden Speed Ki Power. This allows them to jump up to 60ft vertically. Of course, to achieve that they would need to succeed at a DC240 acrobatics check. Needless to say, that is impossible but lets see how close we can get.
Our base speed of 90ft gives us +24 to our acrobatics. So we've got a max of +44 on a roll of a 20. High Jump costs you 1 Ki Point and as a level 20 Unchained Monk it gives you +30 to your acrobatics check. Now we can reach +74. Sudden speed costs another ki point and gives us +30ft to our movement speed, so we gain another +12. We are up to 86. A ring of jumping gets us up to 96, a Rod of Balance gets us up to 106. Boots of Vaulting get us up to 116. An elixer of agility alongside an elixer of forceful exhelation gets us another +6 for a 122 acrobatics check. An exlixer of tumbling gets us up to 132. A sufficiently strong caster or wand of Jump gets us another +30, so we're up to 162. Slap on some cybernetic legs and we've got us up to 172. The soaring sprinter trait ups that to 174, the Totem Spirit feat gets us up to 176, Planar Infusion gets us to 178, Acrobatics gets us to 182, skill focus to 188. A masterwork tool pushes us to 190. Then we add in 20 ranks of acrobatics to get us to 210, another +3 from it being a class skill as a monk for 213. Then we get to add in our dexterity modifiers and our wisdom modifiers (Monkey Style feat) to get, oh, lets say +14 from +7 to Dex and +7 to Wisdom. So we achieve, on a natural 20, a roll of 227. That divided by 4, gets us 56 feet, or just over a 55ft straight up in the air.
However, with the Wind Leaper feat you can treat vertical jumps the same as horizontal jumps. This allows you to cut down that 60ft vertical jump down to a DC60 acrobatics check. Which, thanks to all those acrobatics modifiers, is easily achievable. Especially since Wind Leaper gives +10 to your acrobatics checks, pushing our maximum up to 237 or just 3 short of making our 60ft vertical leap even without having any uses of Wind Leaper available.
I'm sure someone can come up with another +3 to your acrobatics, assuming I haven't mucked up and stack unstackable bonuses, but I have work to do.
So, all these modifiers exist to allow Monks to make 60ft vertical leaps!
The more you know.
After a time, rarely are you limited to 30'/20', thanks to haste, various magic items, and so on. Also note that the limit is your maximum movement for the round, not your movement speed; this is generally double your movement speed, assuming you're hustling. Arguably, you can actually long-jump four times your movement speed since you're running (six if you have the Run feat). That's 120' for the average human wearing normal clothing without any particular feats. You'd need pretty crazy Acrobatics to jump that far.
Per Jumping and Falling, you are limited to:
No jump can allow you to exceed your maximum movement for the round.
Per Movement, you are limited to:
Run (x4) – Moving four times speed is a running pace for a character in light, medium, or no armor ( about 12 miles per hour for an unencumbered human, or 9 miles per hour for a human in chainmail) See Table: Movement and Distance for details.
So, for a standard unencumbered character, with a move of 30', the max move per round is 120'. So you can jump 120' max.
A ninja's ki pool halves the jump DC. They also count as having a running start if they have a ki point available. The Acrobatic Master trick gives a +20 acrobatics. The High Jumper trick halves the DCs on vertical jumps.
The Akitonian Blade triples the result of the acrobatics roll for jumping.
The Jump spell gives +10/20/30 to jumping.