Prism Appendix D IRIS

Art copyright  Doug Beekman, used by permissionD.1 What is IRIS?

The IRIS Initiative System is a method of determining when things happen in a combat or tactical situation.  Unlike most traditional systems, it is not based on a "round" or "turn" concept.  Action flows freely and different combatants may attack or act at different frequencies depending on their speeds and other factors.

Because of the elimination of the turn, IRIS can offer greater realism than other systems without significantly increasing paperwork.  For instance, the GM can, off the top of her head, apply modifiers to reflect a wide variety of factors that may speed up or slow down a combatant, without requiring any extra effort or time.

IRIS makes it easy to integrate attacks, movement, and other actions in a combat setting.  Because it results in a "blow-by-blow" account of the battle, it is more dramatic, offering opportunities for daring last-second rescues and complicated maneuvering.

IRIS is also designed to be easily computerizable.  A computer program can take initiative calculations out of the GM's hands without reducing the GM's control over the battle, and could be expanded to do other tasks for the GM such as dice-rolling or keeping track of damage accrued.

D.2 Time

D.2.1 Phases

The unit of time in an IRIS initiative is a phase.  A phase does not correspond to a round or turn.  Phases are numbered, starting at 0 and counting up indefinitely.  Combats rarely if ever last more than a few hundred phases, but if they did, the GM would usually start counting again from 0 upon reaching 1000 to avoid cumbersome numbers.

Normally, a phase lasts 2/3 of a second, so there are 100 phases in a minute.  Some GMs may consider this too slow or too fast a pace for battle.  (It results in an average of just under 3 actions per minute for an ordinary man.)  If your GM wishes to do so, she will simply announce that phases represent some different length of time.  For instance, phases of 1/30 of a second will give combatants on the average an action every second, comparable to the rate in GURPS™.

D.2.2 Counting Phases

The GM keeps track of the current phase number, which increases as phases go by.  Each combatant has a certain phase that his or her next action will occur on; when the GM counts to that number, that combatant may act.  (If more than one combatant has an action on the same phase, both act simultaneously.)

In practice, three popular methods have evolved for keeping track of phases.  The best of the three is the use of a computer program that counts the phases, keeping track of when the next action for each character is and scanning that list every phase.

If you don't have access to such a program, a simple method is to maintain a list showing when the next action for each combatant is.  Some GMs will have players do this for their own characters to reduce the load (of course, the GM must still do this for all NPCs and creatures).  The GM may also note when any upcoming events will take place and watch for them.  (This would include periodic upkeep phases.)

The GM then counts upwards, scanning the list for an action on that phase.  (Or, if the GM is doing it all herself, she can just skim the list for the lowest number.)

A slightly more complicated method involves the use of a sheet of transparency, such as a clear plastic page protector, and some transparency pens, which can be used to write on the transparency and can be wiped off with a damp cloth.  Inside the transparency, the GM will place a sheet of paper which contains the numbers from 0 to 99 with a space next to each one.  The GM would then write on the transparency the name (or an abbreviation thereof) for each combatant next to the phase of their next action.  (Obviously the GM must start counting again at 0 when she reaches 100.)  The GM then moves down the list, erasing actions as they are taken, and writing in new ones as they are rolled.  A big advantage of this is that the GM has a good idea of whose actions will be coming up soon, at a glance.  It also works well when you're using transparency pens for combat maps as well.

D.2.3 Upkeep Phases

Every fiftieth phase is called an upkeep phase.  These phases serve several purposes.  The humblest is that they serve to remind the GM that another half minute has gone by, which is a great help in keeping a sense of perspective on the passage of time.  But the most important is that bleeding takes place on upkeep phase (it is sometimes known as bleeding phase because of this).

D.3 Calculating Actions

D.3.1 Next Action

When a character's action comes up, that action is resolved immediately.  Then the player and GM calculate a value known as Total Delay according to the instructions in the next few sections.  The Total Delay tells how many phases must pass before the character's next action occurs.  Adding the Total Delay to the current phase yields the phase of the character's next action.  When that action comes up, the process will be repeated yet again.

D.3.2 Delay

The most important factor in calculating the Total Delay is the character's Quickness.  In Chapter 11 you used this to calculate a value known as Delay.  This value averages 30 for a normal human, and a lower value means a faster character.  20 is the best a normal human typically achieves, though animals can easily be faster than that.  A delay of 40 is about as slow as any medium-sized living being can get.

If a character is under the effects of some extraordinary situation, such as a magical haste or a speed-up drug, this is the value that is affected.  Something that lets the character act twice as often would halve his Delay.  Similarly, something that slowed the character down to half normal speed would double it.

The GM will assign a Delay for non-human creatures.  30 is average for humans, but 22 is for animals (fast animals like the cats can easily be as low as 15).  Alternately, assign the creature's quickness on a scale where humans range from 1 to 100 (Creatures And Treasures™ uses a scale like this; creatures have "Attack Quicknesses" which translate by way of a table into "first strike points" on this scale); the Delay is equal to 40 - (Q / 5).

D.3.3 Weapon Speed

Different weapons or other forms of attack will give a modifier to the Delay.  This modifier is known as Weapon Speed.  The chart in Chapter 16 lists these Weapon Speeds (in parentheses, after the CO in the Category column) for all weapons.  The GM's Screens later in that chapter show Weapon Speeds for other attacks such as those in Arms Law & Claw Law™.  Remember that a negative number indicates a faster weapon.

Art copyright  Doug Beekman, used by permissionWhen calculating Total Delay you always apply the Weapon Speed of the weapon used by the character on the preceding action, even if the character just dropped it.  For example, if a character fires a bow, then drops it, during an action, you'd use the bow's Weapon Speed even though the character was about to draw a longsword.  The Weapon Speed for the longsword would begin to apply after the character began to use it.

Weapons that must be loaded (typically ranged weapons) will often have two weapon speeds.  The second one (typically the worse one) is the one you'd usually use.  The first one is only used if the weapon did not need to be loaded during the preceding action.  For instance, on the first attack of a battle, if the character is prepared, the weapon may already be loaded and ready; or a magical weapon might load itself.  (Since technological weapons almost always load themselves, virtually all of them have only one Weapon Speed.)

If you think hard about this, you'll notice that it is all slightly off.  Strictly speaking, the Weapon Speed ought to apply just before the action in which that weapon is used, not after, but it's terribly difficult to keep track of things that way.  Doing it the way I've described is much much easier and "close enough."

D.3.4 Fast Attack

An optional skill available at GM's discretion is Fast Attack, which enables characters to improve the effective weapon speed of an attack.  The skill is as follows:

Fast Attack
  (C=BO, S=R, D=+4, U=-25)
  SIM: none
You must specialize this skill by a particular attack; not just by the weapon used, but also by the method (for instance, "dagger thrown" or "sabre and rapier two-handed").  Divide the SV by ten and round off.  Subtract the result from the delay when that attack is used.

D.3.5 Other Actions

When a character isn't attacking with a weapon, you don't apply a Weapon Speed.  Of course, the GM is free to apply some similar value for whatever she is doing.  For instance, a GM might rule that spells are very fast and apply a modifier of -4 to all spellcast actions.  Or the GM might decide that the spellcast speed is proportional to the spell's level and make a formula that uses the spell's level to figure out the modifier.  Remember that an ordinary action that doesn't involve any weapons or other special actions has a modifier of 0.  An action in which your character actually does nothing at all has a -10 modifier, and an action that is saved has a modifier of +5.

D.3.6 Delay Modifiers

The GM can also apply modifiers based on the situation at will.  For instance, a character performing some maneuver (which would normally get a delay modifier of 0) in a room filled to 6" with water might get a delay modifier of +5.

D.3.7 Rushing Actions

The player may choose to rush the action, reducing the delay modifier in exchange for a penalty to the action.  This option is only available when the character is using a skill which is greater than zero, and the player must decide to do this before actually resolving the action.

For a delay modifier of -5, the character takes as a penalty half of her skill.  Another -5 delay modifier reduces the skill in half again (to one quarter of the original value), and so on, up to -20 delay modifier and one sixteenth of the skill.

For instance, a character with a skill of 28 is making an attack.  She could choose to make it with a -5 delay modifier (above and beyond any existing delay modifiers already being applied) using a skill of 14 instead.  Or if she's in a bigger hurry, she could attack with a 7 skill at a -10 delay modifier, or at a 4 skill with a -15 delay modifier, or at a 2 skill with a -20 delay modifier.

See also section D.4.3 for rules on slowing down an action in order to gain a bonus.

D.3.8 The Random Factor

Of course, there's one last factor to be added in, a random factor.  Roll dñ, divide by 10, and round down.  (The shortcut to dividing by 10 and rounding down is simply throwing away the last digit; you have to still roll it, though, to see if the roll went open-ended.)

D.3.9 Total Delay

The sum of all the above is the Total Delay.  Add it to the current phase to figure out the character's next action.

D.4 Actions

D.4.1 What's In An Action?

When a combatant's action comes up, the character must decide what to do.  In this case the important question is whether the desired activity takes up an entire action.

For instance, attacking a foe takes an action.  Spellcasting usually does (though some spells in some systems are instantaneous).  Many other activities, such as applying first aid, take at least an action.  Movement takes an action if it's more than half the character's available movement.

D.4.2 Pushbacks

When the character would like to do something simpler and less time-consuming, such as drawing a weapon, running forward a few steps, or pressing a button, this probably won't take up the full action.  Instead, it acts as a pushback.

The GM decides how many phases this activity should take up.  For instance, drawing a sword usually takes up five phases.  (If the sword is in a hard-to-get-to back scabbard, it might be more; a sword loosened in a convenient scabbard might be less.  Skills like Fast-Draw can also affect the length of the pushback.)

The character's current action is "pushed back" by that many phases.  This works much like a miniature version of taking an action.  For instance, if the character's current action is on phase 37 and he takes a 5-phase pushback, his next action is changed to 42.

A typical use of a pushback is when a character draws a weapon and then attacks.  When the action comes back around, the attack is resolved.  Another common use is moving before attacking.  In this case, the pushback length is equal to the percentage of the character's total available movement used, multiplied by 30.

Characters may string together several pushbacks.  However, it's usually a lot easier for everyone if the character just decides to spend the whole action doing all these activities.

There is a summary of common pushback values on the "Combat and Initiative Charts" page of the GM's Screens in Chapter 16.  Also note, on the same page, that many activities that are pushbacks also give penalties to the attack.

The GM is entirely within her rights to enforce a brief pushback on a character if the player is indecisive and wants to take some time to figure out what to do.  It's only fair to assume the character is doing the same thing.

D.4.3 Slowing Actions

Just as a character can rush an action by taking a penalty, so too a character can slow an action in order to gain a bonus.  Such slowdowns are done as pushbacks.  As with rushing an action, the character may only slow an action if she has a skill more than zero and decides to do so before resolving the action.

By taking a ten phase pushback before carrying out the action, the character will get a bonus equal to half her skill.  For instance, a character with a skill of 28 who takes a ten phase pushback can act with a skill of 28 + 14 or 42 (11/2 times her original skill of 28).

The character can take up to four ten-phase pushbacks, each worth half as much bonus as the previous one.  For example, two ten-phase pushbacks (or the equivalent, one twenty-phase pushback) allow her to act with a skill of 28 + 14 + 7 or 49 (13/4 times her original skill).  Thirty phases of pushback yields an effective skill of 28 + 14 + 7 + 4 or 53 (17/8 times her original skill).  With forty phases of pushback she can act with a skill of 28 + 14 + 7 + 4 + 2 or 55 (115/16 times her original skill).

At the GM's option, a successful attack made on the character during these pushbacks, or something equally distracting, can ruin the character's concentration.  The character may still act, but loses the bonus (or part of the bonus).

D.4.4 Activities After The Main Action

It sometimes happens that a player would like his or her character to do a normal action such as an attack and follow it with some type of activity that would normally be a pushback.  For instance, a character might attack a foe, drop his weapon, and draw a new one, in one action.

There are two ways to deal with this.  The simpler alternative to understand is to simply resolve the main action, then tell the player to bring up that other activity next action, when it will become a pushback.  But to save a few steps the GM can figure out how many phases the pushback would have been and apply that amount as a Delay Modifier straight-away.

Art copyright  Lou Frank, used by permissionD.5 Saved Actions

D.5.1 Saving An Action

Instead of taking an action, you can save it for later.  Later, you can take this saved action at any time, even just as someone else is about to take their action, possibly preventing someone from doing something.  Saved actions add to the excitement and realism of the game.

When you save an action, you roll your next action just as if you'd taken it.  The Delay Modifier is +5, and combat continues as normal.  You must keep track of how many saved actions you have; you may never have more than three at one time.

One situation in which saved actions are used, that you might not realize at first, is when someone is holding a weapon on someone else.  For example, a bank robber is holding a gun to the head of a hostage.  If someone starts to make a move, the robber can take a saved action and shoot the unfortunate hostage.

D.5.2 Interrupting

You can take your saved action at any time, even when someone else is about to do something.  For instance, you can take a saved action just as a foe is about to attack you, and run away.  In cases like this the GM still must determine if the person taking the saved action can act in time to prevent something.  For instance, if someone is holding a gun on you point blank, and it's his action, and you take a saved action, you can't use it to run around behind him.  You would start to do so but he would still take his action (he happen almost simultaneously) and you still get shot.  However, if the foe was charging at you with a lance, you would have no trouble jumping to the side, perhaps to watch the attacker charge over a cliff concealed behind you.

Essentially, the player calls out that she will take a saved action, and the GM acts from then on as if that character just received an action.  If the character is interrupting an action, the GM could consider that the interrupter's action is coming up just before, perhaps half a phase earlier.  Another combatant can interrupt the interrupter as well.

D.5.3 Restrictions on Saving Actions

There are two restrictions on interruptions.  First, no combatant may ever use saved actions to have two actions within two phases of one another.  For instance, if a character took an action on phase 82, she could not take a saved action until phase 84.

Furthermore, whenever a character takes a saved action, the GM rerolls that character's next action based on the interruption action.  For instance, if a combatant had his next action on phase 134, and on phase 111 he took a saved action, the GM would erase the 134 and then calculate the character's delay based on whatever he did on phase 111.  If it added to a Total Delay of 37, the character's next action would now be 148.  The old roll of 134 is ignored.

D.6 Combat Effects

D.6.1 Bleeding

As mentioned previously, bleeding occurs as indicated on the combat charts every upkeep phase.  Similarly, if a critical effect indicated a number of "rounds until death" upkeep phases are used to count these down.

Art copyright  Gregory Walsh, used by permissionD.6.2 Stuns

All stuns, stun/no-parries, must parry rounds, and rounds spent "down" or "out" indicated on the critical charts will last one action.  A character who is "down" or "out" may do nothing; one who is stunned/no-parry may only make trivial actions like turning; one who is stunned may make only defensive actions like movement.  When a character receives a stun effect in a critical, he will spend his next action "using it up."  The +20 to hit a stunned foe lasts until the character gets an action on which he has no stun effects.  The most serious stun effects occur first.  If a character has saved actions, she may take them to use up stun effects, but may not act (except as specified above) until all stun effects are used up.

D.6.3 Lost Initiative

When a combatant gets a critical which indicates a lost initiative action, he will simply have to take a +10 pushback before his next action.  Several rounds of lost initiative become several actions having a +10 pushback before them (rather than one big pushback).

D.6.4 Parrying

Whenever a character parries, the parry DB is in effect from the action on which the parry was done until the next action that character has.  Even if a fast foe gets more than one action in that period, the parry counts against him or her for the whole time.  If a slow or stunned foe gets no actions during that interval, the parry still ends at the parrier's next action.

D.7 Starting A Combat

D.7.1 Switching to Tactical Time

Typically, the standard, unstructured flow wherein the GM describes situations and the characters respond, turns into a combat because of some specific event.  For example, a character may attack another one, or someone may charge in with a weapon drawn.  The GM decides when to switch to "tactical time" (i.e., when the pace of events mandates an initiative).

D.7.2 Phase 0 Actions

That first event that triggered the whole thing happens on phase 0.  In many cases only one combatant acts at this point, the one that started it.  Sometimes many characters may act.  For instance, in an ambush, a group of combatants may, at some signal, lunge as one to start a battle.  Or the battle might start in the same manner as a sporting event: all participants stand ready waiting for some signal.

Regardless of who acts on phase 0, everyone rolls their next action as if they had acted on phase 0.  Those who did do something roll their next action normally.  Those who didn't, roll it as if they had "done nothing" on phase 0 (which is, after all, the truth); that is, they get a -10 Delay Modifier for their rolls.

D.7.3 Surprise

Of course in many battles some of the combatants are, to varying extents, surprised and unable to recover their wits as quickly as others.  In this case, those characters who are surprised by the beginning of a combat situation will incur a penalty to their Total Delay used to calculate their first action after phase 0.  The amount of the modifier varies with how surprised they are.  Even a small amount of surprise is worth +10 (which cancels their -10 "do nothing" modifier) and a normal amount of surprise is usually worth +25 or more.  The GM may assign this value (possibly based on the combatant's Perceptivity or the results of a roll) or simply use +25 for all surprised combatants.

D.7.4 Initial Saved Actions

In contrast, characters who have had a chance to prepare may come into a battle with some saved actions.  Those who are preparing an ambush for opponents, and who have lots of time to prepare, will typically have 2 or 3 saved actions each.  On the other hand, imagine a party waiting in ambush for a group coming down a road.  If the ambushers have been waiting for an hour, and then have only a minute's warning that the victims have arrived, they will probably only have one saved action each.  You can't expect someone to stay "on the edge of his seat" forever.

The GM (of course) has final say in determining how many saved actions, if any, combatants have on entering a battle.  Logically, surprised combatants may not have saved actions.  Characters who have all the time they need to get prepared before they jump into a fray can always have three if they desire.  Anything in between is up to the GM.

Art copyright  Doug Beekman, used by permissionD.8 An Example

Alek, Fladd, and Spigh are trying to divvy up some loot, and a conflict develops.  Fladd seems to want more than what Alek and Spigh think is his share.  Suddenly, Fladd (who has secretly slipped a knife from his scabbard) swings at Spigh.  The attack is resolved; Fladd's grip was weak, and he dropped the knife.  However, Alek and Spigh are slightly surprised by the attack.  (Only slightly.  They were, after all, in a situation bordering on combat.)

The GM begins initiative after Fladd's attack.  Fladd rolls his Total Delay from phase 0, but Alek and Spigh are slightly surprised; Alek gets a +10 Delay Modifier, Spigh gets a +15.

Alek's Quickness is low, so his Delay is 34.  He rolls a 6, and has a -10 Delay Modifier for having done nothing on his previous action.  With his +10 due to surprise, his Total Delay is 40.  Fladd, however, has a 26 Delay and rolls a 8; he also has a -5 weapon speed, since he just used a dagger.  His first action is on phase 29.  Spigh is the fastest of them all, with a Delay of 22 and a -10 modifier for having done nothing but a +15 for surprise; he rolls a 4, and so goes on phase 31.

On phase 29, Fladd gets his next action.  He draws another knife; this is a pushback of five phases, so he will get to use the knife on phase 34.  Before he gets it all the way out and ready, on phase 31, Spigh recovers from his surprise and threatens Fladd.  In game terms, he saves his action.  He rolls for his next action, getting a Total Delay of 28, and thus acting again on phase 59.

Fladd, unimpressed, continues with his intended attack on phase 34; at this point, Spigh realizes he has no weapon drawn, and that Fladd means to throw his knife, not melee with it as he'd expected.  Spigh interrupts Fladd, pulling his pistol: a pushback of only 3, since it is handy.  His pistol will be ready for firing on phase 37; however, that's not soon enough to stop Fladd from throwing his knife, so Fladd lands a blow in Spigh's arm, causing him to bleed at four hits per "round".  Spigh is also stunned for two "rounds".  Fladd now calculates his Total Delay.  His own Delay of 26, his weapon speed of -5, and the roll of the dice get added in.  However, he rolls high open-ended (on dñ, a 173, therefore a 17) and doesn't get to go until 38 phases from now, or phase 72.

On phase 37 Spigh has finished drawing his pistol, but unfortunately for him, he is now stunned, and can only parry with it.  He rolls an 8, adding his Delay of 22, and gets to go 30 phases from now, or on phase 67, instead of 59 as previously rolled.

On phase 40, Alek finally acts.  Thinking quick, he tosses the coins he was holding at Fladd; the GM rules that this is a pushback, not a whole action, so Alek will get to go again after 8 phases.  The coins slightly startle Fladd, but have no other effect.  On phase 48, Alek kicks Fladd, knocking him over and causing him to "lose initiative."  Alek rolls for his next action, and ends up with a Total Delay of 34; he goes again on phase 82.

Phase 50 comes around, and Spigh bleeds his four hits per round.  On phase 67 Spigh uses up his other stun round.  When his next action comes, on phase 101, he will be no longer stunned.

When phase 72 comes around, Fladd would have had his action, but he has suffered a "lost initiative" critical effect, and so takes a +10 pushback until phase 82.  When phase 82 arrives, Alek and Fladd act simultaneously: both draw sabres, a pushback of 5 for both.

On phase 87, they both act simultaneously again, attacking.  Alek parries, but Fladd does not.  Alek's parry is in effect starting right now, including Fladd's attack, and right up to Alek's next action.  Neither makes a successful attack.  After the initiative rolls, Alek's next action will be on phase 123, and Fladd's on phase 110.

On phase 100, Spigh bleeds yet more.  He tears off his headband and wraps it around the wound (using his First Aid skill), reducing the flow a bit, during his action on phase 101; his next action turns out to be on phase 138.

Phase 110, and Fladd's next action arrives.  A quick feint and thrust leaves Alek dropping his sabre, clutching at a welling red stain.  Poor Alek will be dead in 12 "rounds" (twelve upkeep phases, or six minutes).  The GM erases his action on phase 123, as he is down and out and probably will be for the rest of the combat.  Fladd also takes a small movement, after his attack, to get behind cover, fearful of Spigh's pistol.  This is 10% of his available movement, so his delay modifier is +3 phases.  Including this, his Delay, the weapon speed of his sabre, and his roll, his Total Delay is 31, so his next action will come up on phase 141.

On phase 138, Spigh moves around the back of the bookshelf Fladd is hiding behind, using 16% of his total movement.  He gets a pushback of 4.8 (rounded to 5) phases; on phase 143, he will be able to make an attack, though at -16.

Before that happens, Fladd gets his action on phase 141.  Even more fearful of the pistol, now that it is moving into view and he has no more cover, he flees, using all of his movement.  This takes his whole action; his next action will be on phase 164.  However, it is only three phases -- two seconds -- before Spigh levels his pistol and fires.  Fladd didn't have time to get out of point blank range, and is gunned down by Spigh's marksmanship.  The GM declares that the tactical situation is over.

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