RogerBW's Blog

GURPS house rule: completion time 03 February 2017

This is a small extension of the GURPS rules to generate the time taken for tasks of variable length.

GURPS is generally quite fuzzy about how long it takes to do things, because there are plenty of external factors, but sometimes the exact amount of time matters. For those situations, we have the under-used Time Spent rules on p. B346: you know how long the task "should" take, you decide how long you want to take over it, and the difference gives you a penalty or bonus to your skill roll.

This house rule allows you to invert that for a situation in which you don't really care about degree of success or failure, but simply want to know how long it takes to do the job: can you get the lock picked before the bad guys come round the corner?

Make the skill roll without any modifiers for time spent. Take the margin of success, and convert that back to a duration using the Time Spent rules: pass by 5, and the job is done in half the time (i.e. the amount of time which would give you a -5 for haste). For tasks which can reliably be done eventually but may take a while, such as solving a puzzle, you can also use the margin of failure: miss the roll by 3, and you'll achieve the objective, but it'll take eight times as long as expected.

The main thing to watch out for here is that the task needs to be a binary one: "is the lock picked", "is the security pad bypassed". If you need margin of success for something else ("have I broken into this computer sneakily enough that I won't be noticed"), it can't also be used to generate time taken.

Tags: gurps rpgs

  1. Posted by John Dallman at 11:05am on 03 February 2017

    OK, that makes sense. The asymmetry in the time vs. skill progression for going faster or slower is part of the rules on B346. Critical failure presumably means you mess the job up in some way, and critical success that you find some really good way to do it?

  2. Posted by RogerBW at 11:42am on 03 February 2017

    I think the trick is to keep this to situations where quality of success really doesn't matter, so that one isn't tempted to overload the result. Meaningful results come between success by 9 (which will often be a critical too) and failure by 5 (which may well be a fumble, especially with task difficulties taken into account); I don't want to say that Mr Skill 10 jumps straight from success-by-5 to best-possible while Mr Skill 15 doesn't.

    Failure by more than 5 should count as failure at the task, I think.

    A cruel GM may wish to make the roll in secret, and not tell the player the duration.

Comments on this post are now closed. If you have particular grounds for adding a late comment, comment on a more recent post quoting the URL of this one.

Search
Archive
Tags 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s 2000s 2010s 3d printing action aeronautics aikakirja anecdote animation anime army astronomy audio tech base commerce battletech beer boardgaming bookmonth chain of command children chronicle church of no redeeming virtues cold war comedy computing contemporary cornish smuggler cosmic encounter coup cycling dead of winter doctor who documentary drama driving drone ecchi espionage essen 2015 essen 2016 essen 2017 existential risk falklands war fandom fantasy film firefly first world war flash point food garmin drive gazebo geodata gurps gurps 101 harpoon historical history horror hugo 2014 hugo 2015 hugo 2016 hugo 2017 hugo-nebula reread in brief avoid instrumented life kickstarter learn to play leaving earth linux mecha museum mystery naval non-fiction one for the brow opera perl photography podcast politics powers prediction privacy project woolsack pyracantha quantum rail ranting raspberry pi reading reading boardgames social real life restaurant reviews romance rpg a day rpgs science fiction scythe second world war security shipwreck simutrans south atlantic war squaddies stationery steampunk stuarts suburbia superheroes suspense television the resistance thirsty meeples thriller tin soldier torg toys trailers travel vietnam war war wargaming weather wives and sweethearts writing about writing x-wing young adult
Special All book reviews, All film reviews
Produced by aikakirja v0.1