The Grue
2016-03-25, 12:57 PM
Hello Playgrounders.
Over the past year I've been slowly introducing Lovecraftian elements and themes into my regular group's D&D sessions, and they're absolutely loving it. More recently I've pitched the idea of running a straight up Call of Cthulhu campaign, a pitch that the group accepted unanimously.
The campaign is the CoC classic Beyond the Mountains of Madness. I'm planning to run it using the CoC d20 book for several reasons I won't get into here(and let's please avoid the debate over whether d% or d20 is the objectively superior system :smallwink: ) - that obviously necessitates a conversion, and there are rules available for converting characters, monsters and gods from BRP to d20...
...but there are no rules for converting actual skill tests as written in modules. Where d20 calls for skill tests against a DC that varies with the challenge, BRP typically only calls for a roll of the dice, and very occasionally at half or double the character's skill rating.
Mathematically, of course, if a character in a BRP system has a skill rating of 60%, they have a 60% chance of success at any test against their full skill rating. The problem is that a d20 character's chance of success varies with the task. My initial instinct is to use the book's guidelines for direct skill conversion - take the BRP rating and divide by ten, so that a character with a rating of 60% now has a skill bonus of +6. Such a character has a 60% chance of success against a DC of 15. Leaving aside the fact that d20 characters follows a pattern of consistent growth rather than diminishing returns, should I simply use DCs of 15, 10 and 20 for skill tests at full, double or half rating respectively? Is my math wrong? Is there another approach I could use? Or should I just wing it?
I welcome your responses and suggestions.
Over the past year I've been slowly introducing Lovecraftian elements and themes into my regular group's D&D sessions, and they're absolutely loving it. More recently I've pitched the idea of running a straight up Call of Cthulhu campaign, a pitch that the group accepted unanimously.
The campaign is the CoC classic Beyond the Mountains of Madness. I'm planning to run it using the CoC d20 book for several reasons I won't get into here(and let's please avoid the debate over whether d% or d20 is the objectively superior system :smallwink: ) - that obviously necessitates a conversion, and there are rules available for converting characters, monsters and gods from BRP to d20...
...but there are no rules for converting actual skill tests as written in modules. Where d20 calls for skill tests against a DC that varies with the challenge, BRP typically only calls for a roll of the dice, and very occasionally at half or double the character's skill rating.
Mathematically, of course, if a character in a BRP system has a skill rating of 60%, they have a 60% chance of success at any test against their full skill rating. The problem is that a d20 character's chance of success varies with the task. My initial instinct is to use the book's guidelines for direct skill conversion - take the BRP rating and divide by ten, so that a character with a rating of 60% now has a skill bonus of +6. Such a character has a 60% chance of success against a DC of 15. Leaving aside the fact that d20 characters follows a pattern of consistent growth rather than diminishing returns, should I simply use DCs of 15, 10 and 20 for skill tests at full, double or half rating respectively? Is my math wrong? Is there another approach I could use? Or should I just wing it?
I welcome your responses and suggestions.