The Process of Fixing Jump
Posted: Sat Jan 03, 2009 2:08 am
Principle 1: Jump needs to be a worthwhile way of getting around, and not a waste of skill points past about level 5.
Principle 2: A 1st level character should be able to manage a realistic jump.
So, let's set our baseline: A running long jump roll of 20 by a 1st level specialist (4 ranks, 18 str, and +5 from feats, total modifier +13) should match the world record. Since I don't care to go and actually look for a source I don't already have, I'll use this one, giving a world record just short of 30 feet.
So that gives 30 feet on a roll of 33. This is actually worse than in the PHB, so let's recalibrate so that we're designing a Jump skill that is clearly magical. Let's give the world record to a realistic 1st level monk PC. He doesn't put STR first, instead putting a 14 in it. He didn't put feats into his Jump skill, instead taking feats that made him better on the ground. This gives him a total modifier of +6.
To make the math easier, let's use a baseline DC of 25, for a jumping distance of 30 feet.
Now we need to scale it: The current system of linearly scaling it is, quite frankly, insulting. Each skill point you put in Jump is an extra foot you can clear with a running long jump. Are we seriously supposed to believe that obstacles are supposed to grow by only one foot in width per level?
Not to mention that epic characters can't even attempt truly epic jumps without having several feats to double their jumping distance and stacking them like crazy.
So, let's integrate that into the base skill. For every 5 points your check result increases by, your jumping distance doubles. Get rid of everything that doubles your jumping distance, and keep the old 3.0 rule about limiting your jumping distance by your height out.
Scaling this down, though, makes your jumps unrealistically short. So let's fix that, too, by not throwing away the SRD linear rule (Jumped distance = 1 foot * check result; count only complete squares). It turns out that the linear rule is better up to a result of 24, although at 23 they're about even.
Then, of course, all you need is the exponential table:
For a skill result of 23 to 32, your jumping distance is (30 feet) * 2^((check-25)/5). For a check result greater than 30, you take the last digit of your result and look up a match, then multiply by 4 for every 10 in the difference.
So, the table's first draft. Square values (the results you care about) are given in parentheses; these are rounded normally, not always down, since D&D never expects players to calculate exponential functions at the table; the actual distances are more relics than anything else:
24 26 feet (5 squares)
25 30 feet (6 squares)
26 34 feet (7 squares)
27 39 feet (8 squares)
28 46 feet (9 squares)
29 52 feet (10 squares)
30 60 feet (12 squares)
31 68 feet (14 squares)
32 80 feet (16 squares)
33 92 feet (18 squares)
Use square values, not actual distances, when computing jump distances for check results above 30.
---
This does what we want, but it's a bit clumsy for the game, considering that it has a look-up-the-last digit table that runs from 24 to 33.
So, let's fix this, by taking away the concrete distances and abstracting it further. As an added bonus, we can get rid of that pesky exponential function from the definition:
A Jump result of 20 or less jumps a number of squares equal to the check result divided by 5. A Jump result between 20 and 30 jumps 4 squares, plus one square per two points by which the jump check exceeds 20 (putting a 25 at a jumping distance of 6 squares, which is still what we wanted). A Jump result greater than 30 jumps 9 squares, plus one square per point by which the jump check exceeds 30; each additional 10 doubles the number of squares per point on the check.
Let's make the math even more convenient and assign a jumping distance of 9 squares to 29, and 10 squares to 30.
The results then look like this:
1-20: 1 square per 5
21-27: 4 squares, plus one square per 2 above 20
28-40: 1 square per 1 above 20
41-50: 20 squares, plus two squares per point above 40
51-crazytown: See 41 to 50, and double for every 10 above 40.
Doubling might be too crazy; instead, one could just add one square per point per 10 points (making it quadratic, rather than exponential); a jump result of 50 still covers 40 squares, but each additional point would be 3 squares (until a result of 60 covers 70 squares).
Other jumps are almost fine (jumping distance is halved, not the check result, for a standing jump), when based on the running long jump, except that high jumps that take you no higher than the peak of an equivalent long jump are insulting. To fix this, a high jump is straight up, and its height is 1/2 (not 1/4) the distance of an equivalent long jump. A running high jump includes a horizontal distance equal to either 1/2 of the vertical distance or the speed used to get a running start (a character with a land speed of 6 squares who moves 4 and jumps 24 squares into the air or more still moves 6 squares horizontally; the distance moved is irrelevant, only the speed used to do it is), whichever is less.
The distance travelled by a jump in its primary direction is a maximum; a jumper can voluntarily make a shorter jump. Kinda obvious, but not stated, and it avoids DM dickery.
Let's also add secondary direction reduction; a jumper might want to, for instance, hurl themselves directly forward, when, for example, they have a low ceiling above them. By taking a -4 penalty on the jump check (before making the check), a jumper can halve the distance covered in the secondary direction; each additional halving is a -2 penalty, and they stack in the normal way. So it's possible, at a penalty, to clear a chasm 40 feet across in a room with 10-foot ceilings (Assuming a vertical distance maximum of 2.5 feet, the penalty would be -6, so clearing the chasm would take a jump check of 34. A 20-foot chasm has a penalty of only -4, and so only takes a check result of 24).
Now that we have suitable epic jumping distances, we need to change the action type. Making it be part of a move, and eat movement speed, is insulting. There's no reason to jump at all unless something is in the way, and having points put in to "unless something is in the way" is horrible.
Jumping is a standard action, and allows you to move your jumping distance. A running jump is a full-round action, and allows you to move your land speed, plus your jumping distance. Jumping counts as running, but people with at least 5 ranks in Jump keep their dex to AC, and, if they have 5 ranks in both skills, can tumble at no penalty.
A jumping charge is just like a normal charge, except instead of a double move, you make a running jump.
Abilities that hand out obscene bonuses to Jump checks now have to get toned down, of course, since they were only balanced when they gave bonuses to a skill that made bonuses meaningless. Let's start with the Jump spell. Let's drop it to either one of:
A +CL bonus to Jump checks
or
A +5 bonus to the target's next jump check if running; or the target's next jump counts as running if standing.
Comments? Better fixes? Fixes for the rest? I was typing this to post as I thought of it, so you just read the entire revision and editing process for it.
Current version of the fix:
Principle 2: A 1st level character should be able to manage a realistic jump.
So, let's set our baseline: A running long jump roll of 20 by a 1st level specialist (4 ranks, 18 str, and +5 from feats, total modifier +13) should match the world record. Since I don't care to go and actually look for a source I don't already have, I'll use this one, giving a world record just short of 30 feet.
So that gives 30 feet on a roll of 33. This is actually worse than in the PHB, so let's recalibrate so that we're designing a Jump skill that is clearly magical. Let's give the world record to a realistic 1st level monk PC. He doesn't put STR first, instead putting a 14 in it. He didn't put feats into his Jump skill, instead taking feats that made him better on the ground. This gives him a total modifier of +6.
To make the math easier, let's use a baseline DC of 25, for a jumping distance of 30 feet.
Now we need to scale it: The current system of linearly scaling it is, quite frankly, insulting. Each skill point you put in Jump is an extra foot you can clear with a running long jump. Are we seriously supposed to believe that obstacles are supposed to grow by only one foot in width per level?
Not to mention that epic characters can't even attempt truly epic jumps without having several feats to double their jumping distance and stacking them like crazy.
So, let's integrate that into the base skill. For every 5 points your check result increases by, your jumping distance doubles. Get rid of everything that doubles your jumping distance, and keep the old 3.0 rule about limiting your jumping distance by your height out.
Scaling this down, though, makes your jumps unrealistically short. So let's fix that, too, by not throwing away the SRD linear rule (Jumped distance = 1 foot * check result; count only complete squares). It turns out that the linear rule is better up to a result of 24, although at 23 they're about even.
Then, of course, all you need is the exponential table:
For a skill result of 23 to 32, your jumping distance is (30 feet) * 2^((check-25)/5). For a check result greater than 30, you take the last digit of your result and look up a match, then multiply by 4 for every 10 in the difference.
So, the table's first draft. Square values (the results you care about) are given in parentheses; these are rounded normally, not always down, since D&D never expects players to calculate exponential functions at the table; the actual distances are more relics than anything else:
24 26 feet (5 squares)
25 30 feet (6 squares)
26 34 feet (7 squares)
27 39 feet (8 squares)
28 46 feet (9 squares)
29 52 feet (10 squares)
30 60 feet (12 squares)
31 68 feet (14 squares)
32 80 feet (16 squares)
33 92 feet (18 squares)
Use square values, not actual distances, when computing jump distances for check results above 30.
---
This does what we want, but it's a bit clumsy for the game, considering that it has a look-up-the-last digit table that runs from 24 to 33.
So, let's fix this, by taking away the concrete distances and abstracting it further. As an added bonus, we can get rid of that pesky exponential function from the definition:
A Jump result of 20 or less jumps a number of squares equal to the check result divided by 5. A Jump result between 20 and 30 jumps 4 squares, plus one square per two points by which the jump check exceeds 20 (putting a 25 at a jumping distance of 6 squares, which is still what we wanted). A Jump result greater than 30 jumps 9 squares, plus one square per point by which the jump check exceeds 30; each additional 10 doubles the number of squares per point on the check.
Let's make the math even more convenient and assign a jumping distance of 9 squares to 29, and 10 squares to 30.
The results then look like this:
1-20: 1 square per 5
21-27: 4 squares, plus one square per 2 above 20
28-40: 1 square per 1 above 20
41-50: 20 squares, plus two squares per point above 40
51-crazytown: See 41 to 50, and double for every 10 above 40.
Doubling might be too crazy; instead, one could just add one square per point per 10 points (making it quadratic, rather than exponential); a jump result of 50 still covers 40 squares, but each additional point would be 3 squares (until a result of 60 covers 70 squares).
Other jumps are almost fine (jumping distance is halved, not the check result, for a standing jump), when based on the running long jump, except that high jumps that take you no higher than the peak of an equivalent long jump are insulting. To fix this, a high jump is straight up, and its height is 1/2 (not 1/4) the distance of an equivalent long jump. A running high jump includes a horizontal distance equal to either 1/2 of the vertical distance or the speed used to get a running start (a character with a land speed of 6 squares who moves 4 and jumps 24 squares into the air or more still moves 6 squares horizontally; the distance moved is irrelevant, only the speed used to do it is), whichever is less.
The distance travelled by a jump in its primary direction is a maximum; a jumper can voluntarily make a shorter jump. Kinda obvious, but not stated, and it avoids DM dickery.
Let's also add secondary direction reduction; a jumper might want to, for instance, hurl themselves directly forward, when, for example, they have a low ceiling above them. By taking a -4 penalty on the jump check (before making the check), a jumper can halve the distance covered in the secondary direction; each additional halving is a -2 penalty, and they stack in the normal way. So it's possible, at a penalty, to clear a chasm 40 feet across in a room with 10-foot ceilings (Assuming a vertical distance maximum of 2.5 feet, the penalty would be -6, so clearing the chasm would take a jump check of 34. A 20-foot chasm has a penalty of only -4, and so only takes a check result of 24).
Now that we have suitable epic jumping distances, we need to change the action type. Making it be part of a move, and eat movement speed, is insulting. There's no reason to jump at all unless something is in the way, and having points put in to "unless something is in the way" is horrible.
Jumping is a standard action, and allows you to move your jumping distance. A running jump is a full-round action, and allows you to move your land speed, plus your jumping distance. Jumping counts as running, but people with at least 5 ranks in Jump keep their dex to AC, and, if they have 5 ranks in both skills, can tumble at no penalty.
A jumping charge is just like a normal charge, except instead of a double move, you make a running jump.
Abilities that hand out obscene bonuses to Jump checks now have to get toned down, of course, since they were only balanced when they gave bonuses to a skill that made bonuses meaningless. Let's start with the Jump spell. Let's drop it to either one of:
A +CL bonus to Jump checks
or
A +5 bonus to the target's next jump check if running; or the target's next jump counts as running if standing.
Comments? Better fixes? Fixes for the rest? I was typing this to post as I thought of it, so you just read the entire revision and editing process for it.
Current version of the fix:
Jump (Str, Armor Check Penalty)
Check
You use the Jump skill to make jumps. The DC depends on the distance you want to cover and the kind of jump you are attempting.
Jumping is easiest with a running start; the DCs here assume a running start. A jump attempted without a running start suffers a -8 penalty.
If you succeed on your jump check, you land standing. If you land on difficult terrain, you must beat the DC to jump that distance by at least the factor by which it impedes movement (2 for normal difficult terrain, 4 for doubly difficult, and so on) and be trained, or land prone.
Long Jump
A long jump is a horizontal jump, made across a gap like a chasm or stream. At the midpoint of the jump, you attain a vertical height equal to one-quarter of the horizontal distance. A long jump must be made in a straight line.
When you decide to jump, you declare your destination, then roll your check. If you make the DC to jump to that destination, you land there; otherwise, you fall short, travelling the furthest distance possible with your check result.
If you fall one square short when clearing a pit, chasm, canyon, or similar obstruction, you may grab the edge with a DC 15 reflex save; this ends your turn. Getting up requires a DC 15 Climb check; attempting to do so is a move action; while hanging you are considered to be climbing.
Long Jump Distance Tables:
Check Result: Maximum Distance
1-20: 1 square per 5
21-27: 4 squares, plus one square per 2 above 20
28-40: 1 square per 1 above 20
41-50: 20 squares, plus two squares per point above 40
51-crazytown: See 41 to 50, and double for every 10 above 40.
Maximum Distance: DC
1-4 squares: Distance x5
5-8 squares: 12 + Distance x2
8-20 squares: 20 + Distance
21-40 squares: 30 + Distance/2 (round up)
41+ squares: Divide distance by 2 and round up repeatedly to get a number of squares less than 40, use that DC, add 10 for each doubling.
If you have a speed of 40 feet, increase these jumping distances by 1 square. If you have a speed of 45 feet or more, increase them by 2 squares for every 15 feet above 30.
High Jump
A high jump is a vertical leap made to reach a ledge high above or to grasp something overhead. The DC is the eight higher than for a long jump to clear the same distance.
If the check succeeds, you travel along the same horizontal line as you used to get a running start (if you did not have one, you land where you started) a distance equal to 1/2 of your jump height or your speed (of the type used to get a running start), whichever is greater.
Obviously, the difficulty of reaching a given height varies according to the size of the character or creature. The maximum vertical reach (height the creature can reach without jumping) for an average creature of a given size is shown on the table in the SRD entry. (As a Medium creature, a typical human can reach 8 feet without jumping.)
Quadrupedal creatures don’t have the same vertical reach as a bipedal creature; treat them as being one size category smaller.
Hop Up
As part of a normal land move, you may jump onto an object with a height equal to or less than the vertical reach of a character one size category smaller than you. This counts as 10' of movement and requires a DC 10 jump check, running start or no. A check result of at least 20 cuts the cost down to 5', and a check result of 25 removes the cost entirely.
Jumping Down
If you intentionally jump from a height, you take less damage than you would if you just fell. The base DC to jump down from a height is 15. You do not have to get a running start to jump down, so the DC is not doubled if you do not get a running start.
If you succeed on the check, you take falling damage as if you had dropped 10 fewer feet than you actually did. For every 5 by which you beat the DC, you can count the fall as being 10' shorter. This stacks with the reduction provided by Tumble. Even if you fail the check, the first 1d6 damage you take from jumping down is nonlethal. Your own jumps only cause fall damage for the difference in height between the start and endpoints, and only if the endpoint is lower (you may Jump Down as part of a regular jump to reduce this damage).
Jumping Straight
In some circumstances, a jumper may wish to make a jump straight ahead (for instance, when dealing with a dangerous ceiling), or straight up. By taking a -4 penalty on the jump check (before making the check), you can halve the distance covered in the secondary direction (vertically for long jumps, horizontally for long jumps); each additional halving is a -2 penalty, and they stack in the normal way (two halvings reduces it to 1/4, three to 1/8, and so on).
Action
A long or high jump can be made as a move action or as part of a move. Such a jump is considered Standing unless it is made with a running start of at least 20' in a straight line before the jump. A jump made as a move action clears the total distance of the jump; horizontal movement during a jump made as part of a move counts as movement speed (the height of a high jump made to clear an obstacle does not count as movement). If a jump action (a jump longer than would be allowed by movement speed) and a normal move are made in the same round, the movement given by the normal move may be distributed on either or both sides of the jump (i.e., a barbarian with 50' of movement can get a running start, jump 60' across a chasm as a move action, and then finish his original move on the other side).
A Hop Up is part of a move; it is not an action of its own, although it costs movement. Jumping down is likewise part of a move; it is automatic and free whenever your move takes you to a circumstance where using it would be advantageous.
Any turn in which you jump is counted as though you were running for purposes of fatigue.
Try Again
Circumstantial. A failed jump check (one that does not allow you to travel your target distance) indicates that you fall short; if untrained, you also fall prone. If trained, you only fall prone if you fail and roll a natural 1 on your check, or if you land in circumstances different from those you intended to land on, such as landing on rubble or in a pit that you failed to clear, or impacting a wall you attempted to jump over. You may, however, attempt to jump again if your landing site permits it.
Synergy
If you have at least 5 ranks in Tumble, you gain a +2 bonus to Jump checks and can attempt to tumble as part of a jump; this does not reduce your jumping distance.
If you have at least 5 ranks in Swim and Jump, you can attempt to jump while swimming on the surface of a liquid, at a -4 penalty.
If you have at least 5 ranks in Jump, you gain a +2 bonus to Tumble checks.
Check
You use the Jump skill to make jumps. The DC depends on the distance you want to cover and the kind of jump you are attempting.
Jumping is easiest with a running start; the DCs here assume a running start. A jump attempted without a running start suffers a -8 penalty.
If you succeed on your jump check, you land standing. If you land on difficult terrain, you must beat the DC to jump that distance by at least the factor by which it impedes movement (2 for normal difficult terrain, 4 for doubly difficult, and so on) and be trained, or land prone.
Long Jump
A long jump is a horizontal jump, made across a gap like a chasm or stream. At the midpoint of the jump, you attain a vertical height equal to one-quarter of the horizontal distance. A long jump must be made in a straight line.
When you decide to jump, you declare your destination, then roll your check. If you make the DC to jump to that destination, you land there; otherwise, you fall short, travelling the furthest distance possible with your check result.
If you fall one square short when clearing a pit, chasm, canyon, or similar obstruction, you may grab the edge with a DC 15 reflex save; this ends your turn. Getting up requires a DC 15 Climb check; attempting to do so is a move action; while hanging you are considered to be climbing.
Long Jump Distance Tables:
Check Result: Maximum Distance
1-20: 1 square per 5
21-27: 4 squares, plus one square per 2 above 20
28-40: 1 square per 1 above 20
41-50: 20 squares, plus two squares per point above 40
51-crazytown: See 41 to 50, and double for every 10 above 40.
Maximum Distance: DC
1-4 squares: Distance x5
5-8 squares: 12 + Distance x2
8-20 squares: 20 + Distance
21-40 squares: 30 + Distance/2 (round up)
41+ squares: Divide distance by 2 and round up repeatedly to get a number of squares less than 40, use that DC, add 10 for each doubling.
If you have a speed of 40 feet, increase these jumping distances by 1 square. If you have a speed of 45 feet or more, increase them by 2 squares for every 15 feet above 30.
High Jump
A high jump is a vertical leap made to reach a ledge high above or to grasp something overhead. The DC is the eight higher than for a long jump to clear the same distance.
If the check succeeds, you travel along the same horizontal line as you used to get a running start (if you did not have one, you land where you started) a distance equal to 1/2 of your jump height or your speed (of the type used to get a running start), whichever is greater.
Obviously, the difficulty of reaching a given height varies according to the size of the character or creature. The maximum vertical reach (height the creature can reach without jumping) for an average creature of a given size is shown on the table in the SRD entry. (As a Medium creature, a typical human can reach 8 feet without jumping.)
Quadrupedal creatures don’t have the same vertical reach as a bipedal creature; treat them as being one size category smaller.
Hop Up
As part of a normal land move, you may jump onto an object with a height equal to or less than the vertical reach of a character one size category smaller than you. This counts as 10' of movement and requires a DC 10 jump check, running start or no. A check result of at least 20 cuts the cost down to 5', and a check result of 25 removes the cost entirely.
Jumping Down
If you intentionally jump from a height, you take less damage than you would if you just fell. The base DC to jump down from a height is 15. You do not have to get a running start to jump down, so the DC is not doubled if you do not get a running start.
If you succeed on the check, you take falling damage as if you had dropped 10 fewer feet than you actually did. For every 5 by which you beat the DC, you can count the fall as being 10' shorter. This stacks with the reduction provided by Tumble. Even if you fail the check, the first 1d6 damage you take from jumping down is nonlethal. Your own jumps only cause fall damage for the difference in height between the start and endpoints, and only if the endpoint is lower (you may Jump Down as part of a regular jump to reduce this damage).
Jumping Straight
In some circumstances, a jumper may wish to make a jump straight ahead (for instance, when dealing with a dangerous ceiling), or straight up. By taking a -4 penalty on the jump check (before making the check), you can halve the distance covered in the secondary direction (vertically for long jumps, horizontally for long jumps); each additional halving is a -2 penalty, and they stack in the normal way (two halvings reduces it to 1/4, three to 1/8, and so on).
Action
A long or high jump can be made as a move action or as part of a move. Such a jump is considered Standing unless it is made with a running start of at least 20' in a straight line before the jump. A jump made as a move action clears the total distance of the jump; horizontal movement during a jump made as part of a move counts as movement speed (the height of a high jump made to clear an obstacle does not count as movement). If a jump action (a jump longer than would be allowed by movement speed) and a normal move are made in the same round, the movement given by the normal move may be distributed on either or both sides of the jump (i.e., a barbarian with 50' of movement can get a running start, jump 60' across a chasm as a move action, and then finish his original move on the other side).
A Hop Up is part of a move; it is not an action of its own, although it costs movement. Jumping down is likewise part of a move; it is automatic and free whenever your move takes you to a circumstance where using it would be advantageous.
Any turn in which you jump is counted as though you were running for purposes of fatigue.
Try Again
Circumstantial. A failed jump check (one that does not allow you to travel your target distance) indicates that you fall short; if untrained, you also fall prone. If trained, you only fall prone if you fail and roll a natural 1 on your check, or if you land in circumstances different from those you intended to land on, such as landing on rubble or in a pit that you failed to clear, or impacting a wall you attempted to jump over. You may, however, attempt to jump again if your landing site permits it.
Synergy
If you have at least 5 ranks in Tumble, you gain a +2 bonus to Jump checks and can attempt to tumble as part of a jump; this does not reduce your jumping distance.
If you have at least 5 ranks in Swim and Jump, you can attempt to jump while swimming on the surface of a liquid, at a -4 penalty.
If you have at least 5 ranks in Jump, you gain a +2 bonus to Tumble checks.