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coronatiger 09-19-2018 05:12 PM

Moving fast through difficult terrain
 
How do I model running through difficult terrain in GURPS, like cluttered backyards, building sites or wrecked buildings? I don't want to spec up every obstacle, but could assign a general difficulty to the area (and the players could reduce the difficulty with Per rolls to find a smart route).

1. How often should I require the players to roll?
2. Which skills should I allow/require? I'm thinking that Climbing, Jumping and Acrobatics are viable options, possibly Running. Are there other skills that could be used?
3. Should I assign different difficulty levels to each skill depending on the type of obstacles?
4. How do I determine how quickly the characters traverse the area?
5. How could familiarity with the terrain reduce time spent and/or difficulty?

Assume an "out-of-combat" situation, and that the total distance will be somewhere between 100 and 1000 meters. (We won't be doing second-by-second action.)

Dalin 09-20-2018 04:06 PM

Re: Moving fast through difficult terrain
 
Quote:

Originally Posted by coronatiger (Post 2210057)
How do I model running through difficult terrain in GURPS, like cluttered backyards, building sites or wrecked buildings? I don't want to spec up every obstacle, but could assign a general difficulty to the area (and the players could reduce the difficulty with Per rolls to find a smart route).

Interesting challenge. I'm tackling this without my books, so I can't cite precedent or parallel rules. Here's how I would do it:

Quote:

1. How often should I require the players to roll?
I would choose something that makes sense dramatically. If you're not in combat time, then I could see 2-4 rolls for 100-1000 yards.

Quote:

2. Which skills should I allow/require? I'm thinking that Climbing, Jumping and Acrobatics are viable options, possibly Running. Are there other skills that could be used?
3. Should I assign different difficulty levels to each skill depending on the type of obstacles?
My instinct would be to use DX or Acrobatics as the base skill with a flat penalty for my sense of the difficulty and allow the player to pitch another skill as a complementary skill roll. (Maybe the Per check could also be complementary.) Depending on their pitch and the nature of the obstacles, I might allow the complementary bonus to be double (+2 instead of +1, or +4 on a critical success).

Quote:

4. How do I determine how quickly the characters traverse the area?
Well, you know the theoretical top speed for a straight line sprint on clear terrain, so that's the upper limit (e.g., for a typical Move-5 person, they can sprint at 6 so they could cover 1000 yards in 167 seconds). Reduce to whatever makes sense for the terrain. I might think of this in terms of combat time; if, in combat, a character would have to spend 2 extra movement points per turn (on average), then this would reduce top speed to 4 yards per second, giving us 250 seconds for 1000 yards. Or just handwave and pick a number that seems plausible: "Moving fast, with a bit of luck, it'll take about five minutes."

Then adjust based on the skill rolls. Could be simply reducing it a bit for each failure (-10% per failure on four rolls). Critical failure(s) indicate a serious mishap, so you drop out of the race. Or you could come up with something based on the margin of success. That would take a bit more fiddling with odds to come up with a spread that seems reasonable. Critical successes allow you to come up with an unusually clever shortcut that speeds things up (or counts as two successes).

Quote:

5. How could familiarity with the terrain reduce time spent and/or difficulty?
I would adjust the base skill modifier for this. So if you live in the junkyard, you can sprint through it at only -2. The thugs who tried to ambush you there are at -5.

That's my initial take. Curious to hear about other ideas and/or tweaks.

evileeyore 09-20-2018 07:46 PM

Re: Moving fast through difficult terrain
 
It all depends on how gritty you want to make it...

Quote:

Originally Posted by coronatiger (Post 2210057)
Assume an "out-of-combat" situation, and that the total distance will be somewhere between 100 and 1000 meters. (We won't be doing second-by-second action.)

So, cinematicaly non-gritty. Copy.


Quote:

How do I model running through difficult terrain in GURPS, like cluttered backyards, building sites or wrecked buildings?
I usually just decide on a percentage of movement slowed each area might impose.

Quote:

1. How often should I require the players to roll?
Once per 'time unit' you want to cover. Or distance unit? Whatever.

Quote:

2. Which skills should I allow/require? I'm thinking that Climbing, Jumping and Acrobatics are viable options, possibly Running. Are there other skills that could be used?
Area Knowledge makes a good Complimentary Skill to the above.

Quote:

3. Should I assign different difficulty levels to each skill depending on the type of obstacles?
Sure. A fence should be easier to Climb than Acrobatics over and Running is just not applicable (for instance).

Quote:

4. How do I determine how quickly the characters traverse the area?
Calculate how long it would take to traverse the distance, then reduce the time taken as a percentage. Like -10%xMOS. Or -5%. Or whatever you think is good.

Quote:

5. How could familiarity with the terrain reduce time spent and/or difficulty?
See above Area Knowledge Complimentary Skill mention.

Refplace 09-20-2018 07:52 PM

Re: Moving fast through difficult terrain
 
I'd go with 3 rolls for dramatic purposes, or break it up by time units.
I'd use Running as the primary skill here, Complementary skills from Acrobatics, Jumping, Per and perhaps Climbing.
I like the idea of MOS reducing the time taken.

Icelander 09-20-2018 08:33 PM

Re: Moving fast through difficult terrain
 
I'd probably use two rolls, like when driving through traffic and trying to pick the best route.

For selecting a route, I'd allow any of Area Knowledge (anything small-scale that includes this exact area), Observation or Per-based Running.

For actually making one's way through the area, I'd allow a choice of Acrobatics, Jumping or DX-based Running.

Tyneras 09-20-2018 10:18 PM

Re: Moving fast through difficult terrain
 
Map out the encounter as a flowchart or decision tree with a branch for each possible success or failure. This will give you a handle on how much content you actually have, prune boring branches, and see where you have spots that could use more development.

Pursuivant 09-23-2018 03:26 PM

Re: Moving fast through difficult terrain
 
Isn't there a GURPS book which includes rules for Parkour?

That would have useful rules for moving quickly in urban environments.

In rural areas, Survival (Appropriate Terrain) skill should be complementary to Running or Climbing skill. In built-up areas Urban Survival might apply as well, assuming that you're on unfamiliar ground and are trying to find a particular "terrain feature" like a fence, fire escape, or door.

Acrobatics skill could be used for tasks like vaulting over an obstacle or doing a forward roll to quickly go under an overhang.

Don't forget to apply penalties to Vision and require occasional Vision rolls if light conditions are anything less than perfect. It's very easy to run into something, or trip, in the dark.

evileeyore 09-23-2018 11:35 PM

Re: Moving fast through difficult terrain
 
Quote:

Originally Posted by Pursuivant (Post 2210956)
Isn't there a GURPS book which includes rules for Parkour?

There's Dungeon Parkour in DF and DFRPG, but that's dealt with on a turn by turn basis.

Taneli 09-24-2018 04:01 AM

Re: Moving fast through difficult terrain
 
How about the chase rules from GURPS Action 2: Exploits pp 31-35?


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