Making sense of jet and jet-like spells

[Anaraxes]

Originally Posted by Calvin

on the same round they were cast

Some of your confusion, I think, comes from some assumptions that are understandable considering the usual way games are designed. Let's start with this one:

GURPS doesn't have rounds. There's a sequence in which characters take individual turns, around and around. But there's not a higher-layer structure called a "round" that spans some set of those turns. There's not a special "Start of Round Phase" in which some things are tracked and events happen, or an "End of Round Phase" which makes clocks tick. There are just turns.

Thus, there's no 1-second-long round length. The time is approximate as well, but that notional 1 second is the length of time from the start of one character's turn to the start of that same characters next turn. Two characters have turns that overlap slightly, with different start points.

But while I could answer that question for myself, I could not find an answer for what happens to characters with ATR or Great Haste.

ATR is about the perception of time, not the actual passage of it...
further levels of ATR would add further attacks.

So, second hair to split, simply because the jargon might make the point clear:

- ATR isn't about perception. (There's a different advantage, Enhanced Time Sense, that's just about perception, the universe around you "looking slow" even though you're not "moving fast".)

- "Maneuver" is the key word here. That's the thing you choose to describe what you're doing during your turn -- Attack, Move, All-out Defense, etc.

- Most characters get one Maneuver during their turn. But "turn" is not synonymous with "Maneuver". It's possible to have more Maneuvers during one turn.

- ATR is an Advantage that gives you an extra Maneuver per turn. (It might just as well be called "Extra Maneuver".) So, you might Move for your first Maneuver during your turn, and then for your second Maneuver during that same turn, choose Attack. Or, say, Attack and then All-out Defense, so the AoD persists through all the other turns until the start of your next turn.

- The notional time from start-of-turn to start-of-turn is still 1 second, so ATR really does mean you're moving twice as fast, if you choose Move twice. It's not just perception; you're accomplishing twice as much physical activity as the next guy. (Still, ATR is not a complete Flash-like speedster package. Emulating that kind of speed takes a number of other Advantages.)

- There's yet another Advantage called Extra Attack. This one doesn't give you another Maneuver. It adds one attack to the number of attacks you could make during whatever Maneuver you chose, if that Maneuver allows attacks in the first place.

- ATR and Extra Attack multiply. EA 1 means you can make two attacks if you choose an Attack Manever. ATR means you can choose two Maneuvers per turn. If you choose two Attack Maneuvers, then it's (base attack + EA attack) + (base attack + EA attack) = 4 attacks total.

- Casting a spell is the Concentrate Maneuver

- So, with ATR, you can Concentrate, then Attack with your Flame Jet, in the same turn. (Notionally one second by the time you're done, which is to say the start of your next turn; there's not a global clock that you have to wait out before you can attack.)

- As long as I'm dragging in yet other Advantages, see Compartmentalized Mind. We could call this one "Extra Maneuver (Mental Only)". It works like ATR, except that your choices are more limited. It would suit this case, those, since you could (CM) Concentrate=cast and (normal) Attack, for the same net effect as having ATR. Also, multiple levels of CM do allow spells to be cast by "parallel processing". CM 1 plus a base Concentrate would let you cast a "2 second" spell in 1 turn. (CM 59 would let you cast a 1-minute spell in one second.)

When trying to sort out the mechanics, it's really less about time or turns than it is about counting Maneuvers. If you're trying to relate combat to external time, then you measure from start-of-turn to the next for the same character.

With all that under our belt, the Great Haste questions should be clear. Great Haste adds one level of ATR, so the character can do whatever ATR 1 would let them do, and nothing extra or different. They're the same thing. Casting Great Haste on someone with ATR 10 means they have ATR 11 (not ATR 20), so it's not a straight multiplier on actions accomplished.

The last point is that GURPS is not written with the attitude adopted by a number of other games, that the rules are meant to be interpreted literally and mechanically, while any quirks or ways to stack something until the system breaks that you find are intentional meta-tactics meant to be exploited. (Good-on-yer!) The rules are meant to be interpreted by consenting adults working together to have fun. If something seems broken, then it's either a problem in understanding the intent, or -- you know -- just a broken rule. It's not a designed loophole that's supposed to be there if only you follow the text literally.

So, despite my being picky about the jargon above, I'm not trying to give you the impression that there's this precise sequence you have to follow. I'm just using the terminology hopefully for one benefit of jargon, to make understanding the intent more clear.