Spell Durations

This article provides alternate rules for calculating duration and duration scaling costs for spells. They replace the existing duration cost tables in College of Magics and any duration scaling options listed in the descriptions of specific spells.

1. Duration Costs

The big problem with HARP College of Magic spell duration costs is that it leads to utility spells like Light having a duration of 10 rounds per rank (and Light doesn't even have any duration scaling options). Each round is 2 seconds long, so that's a maximum of 120 seconds for a 1st level character. Or 330 rounds (660 seconds or 11 minutes!) for a 10th level character if they've bought the maximum number of ranks allowed per level.

That kind of duration is essentially useless - Light should, as an absolute minimum, last at least a minute per rank (preferably 10 minutes per rank) and be relatively easy to scale up to longer durations.

My guess is that the reason for this is to prevent long durations for spells used in combat. IMO, that's not a problem that needs to be solved -- very few combats last even 10 rounds, so even 2 rounds/rank is more than enough to last the entire combat. A duration of 1 minute/rank is rarely, if ever, going to make even a tiny difference to the outcome of any combat.

Even spells like Fire Wall with a base duration of 2 rounds/rank wouldn't unbalance the game if their base duration was 1 minute/rank - at most, it makes it slightly easier for PCs (or NPCs) to run away and avoid being captured or killed. The chaser has to wait minutes rather than seconds before they can get past the wall and give chase - or just cast Dispel Magic.

Outside of combat, a Mage being able to cast Mage Armor or other spells that last tens of minutes or even hours isn't game-breaking. At worst, it means they don't have to spend the first round casting Mage Armor again.

So, to fix a non-problem, the HARP CoM spell creation rules cause seriously broken durations for Utility spells like Light, Fly, Water Breathing and many others -- these spells are almost completely useless with durations of 2 or 5 or 10 rounds per rank, even a 20th level caster with the maximum 63 ranks is only going to get 630 rounds (21 minutes) out of Light.

With my duration costs table, it is possible to design a Light spell so that even a 1st level caster with 6 ranks will get a duration of 1 hour.

For example, my version of the Light spell uses a non-standard Conjure (5) Action aspect instead of Create (30). This aspect is only for creating intangible, non-material things like light or illusions.

    NAME: Light
    PP COST: 6
    RANGE: Touch
    DURATION: 10 minutes/rank
    SPELL TYPE: Utility
    RR: --
    SPHERES: Universal
    ACTION ASPECTS: Conjure (5)
    OBJECT ASPECTS: Light (5); Cloud (15) = 20
    ATTRIBUTES: Range: Touch (10); AoE: Radius 20' (30);
                Duration: 10 minutes/rank (50) = 90

Without a Conjure aspect, there is no way that the HARP Light spell could cost any less than 9 or 10 PP (depending on whether it requires the Cloud (15) aspect or not - and, IMO, it should) - at least, not without reducing the radius from 20' to 10' and the duration from 10 rounds/rank to 5 rounds/rank. 9 PP requires 9 skill ranks, beyond the reach of a 1st level character.

In fact, many of the spells in the HARP core rulebook do not conform to the Action, Object, or Attribute costs in CoM. They seem to have been hand-tweaked to meet a desired PP cost target. IMO, this is broken - if a formula does not give the desired results, then the correct solution is to adjust the formula until it does, not to apply arbitrary over-rides whenever you don't like a particular result.

Duration Table

Here is the duration cost table I'm using for all my homebrew spells. I also use them for HARP, CoM, HARPer's Bazaar, and Codex spells by converting them as needed - e.g. any duration of "2 rounds/rank" becomes "1 minute/rank".

The "Dormant" duration is used for spells that embed a single casting of another spell into a Rune, Potion, Ward, etc. The embedded spell remains dormant until the rune is read, potion is drunk, etc. I derived it from the "Special (50)" duration for Potion Mastery in CoM

NOTE: I only have the original HARP and CoM rulebooks from 2004, not the newer editions published from 2013. My understanding is that the newer edition of CoM has different duration costs for Utility and Attack spells so that they end up costing 1 or 2 PP more than non-attack spells.

My duration rules don't do that. Instead, I have a non-standard Attack (20) attribute which is required for all attack spells, both those with a Resistance Roll and Elemental/Directed attack spells such as Elemental Bolt, Elemental Ball. This effectively adds 1 PP to the cost of all attack spells.

2. Duration Scaling

When scaling up the duration of a spell, the scaling cost is 1 PP (for changing the duration) plus the difference between the attribute cost of the standard duration of the spell and the scaled duration, divided by 10.

This means that the duration scaling costs vary according to the spell's base duration. That would be a pain to calculate every time, so I've included a handy table below with pre-calculated scaling duration option costs

    Scaling Cost = 1 + ((new duration cost - base duration cost) ÷ 10)

For example, to scale up the Light spell from 10 minutes/rank (cost=50) to 1 hour/rank (cost=100) is +6 PP:

    100 - 50 = 50
    50 ÷ 10 = 5
    1 + 5 = 6 PP

Casting this spell with this scaling option would cost a total of 12 PP - which would require a 3rd-level or higher character.

Concentration Spells:

The following scaling options remove the Concentration requirement from a spell.

If the caster also wishes to scale up the duration, one of them is required before other duration-extending options can be used.

Change Duration (from Concentration Only to 1 minute/rank)        +1 PP
Change Duration (from  1 minute/rank (C)  to 1 minute/rank)       +1 PP
Change Duration (from 10 minutes/rank (C) to 10 minutes/rank)     +3 PP

Duration Scaling Limits

Except as may be mentioned in the descriptions for individual spells, any spell with a duration may be scaled to any other duration.

Elemental/Directed Attack spells have no duration and can not be scaled to have one. While the effects (damage to creatures or objects) may linger, the created element or magical force lasts only until they reach their target.

Like other spells with a duration, RR Attack spells can also be scaled to any duration - after all, spells like Charm or Sleep aren't much use if they only last for 2 rounds (4 seconds) per rank.

Duration Scaling Options Table

Look up the original duration on the vertical axis, and the desired duration on the horizontal axis. The result is the number of additional PP required to cast the spell.

From/To	10m	1h	1d	1w	1mo	1y	P	1m/R	10m/R	1h/R	1d/R	1w/R	1mo/R	1y/R
1m	+2	+4	+5	+6	+8	+9	+20	+2	+4	+8	+10	+12	+15	+18
10m	—	+3	+4	+5	+7	+8	+19	—	+3	+7	+9	+11	+14	+17
1h	—	—	+2	+3	+5	+6	+17	—	—	+5	+7	+9	+12	+15
1d	—	—	—	+2	+4	+5	+16	—	—	+4	+6	+8	+11	+14
1w	—	—	—	—	+3	+4	+15	—	—	+3	+5	+7	+10	+13
1mo	—	—	—	—	—	+3	+14	—	—	+2	+4	+6	+9	+12
1y	—	—	—	—	—	—	+12	—	—	—	+2	+4	+7	+10
1m/R	—	+3	+4	+5	+7	+8	+19	—	+3	+7	+9	+11	+14	+17
10m/R	—	—	+2	+3	+5	+6	+17	—	—	+5	+7	+9	+12	+15
1h/R	—	—	—	—	—	+2	+13	—	—	—	+3	+5	+8	+11
1d/R	—	—	—	—	—	—	+11	—	—	—	—	+3	+6	+9
1w/R	—	—	—	—	—	—	+9	—	—	—	—	—	+4	+7
1mo/R	—	—	—	—	—	—	+6	—	—	—	—	—	—	+4
1y/R	—	—	—	—	—	—	+3	—	—	—	—	—	—	—