Difficulty Class Conversion

xane · 07-12-2019, 05:40 AM

Just some notes on converting Difficulty Class checks, a.k.a. skill checks, from other game systems for use in TFT.

I'd be interested on comments or suggestions.

The assumptions are:
* using average 3d6 attribute scores for a starting character gives a an average of +2 bonus to checks from attribute and class/level bonuses
* the TFT success rate is based on an average attribute score of 10-11 typical of a starting 32 point character.

DC Rating ---- Success- TFT Equivalent
4 ------------ 95% ---- 2d6 (94%)
5 -"very easy" 90%
6 ------------ 85% ---- 2d6 with -1 (87%)
7 ------------ 80%
8 ------------ 75% ---- 3d6 with +2 (78%)
9 ------------ 70%
10 "easy"----- 65% ---- 3d6 with +1 (68%)
11 ----------- 60%
12 ----------- 55% ---- 3d6 (56%)
13 ----------- 50%
14 ----------- 45% ---- 3d6 with -1 (43%)
15 "medium"--- 40%
16 ----------- 35%
17 ----------- 30% ---- 3d6 with -2 (31%)
18 ----------- 25%
19 ----------- 20% ---- 4d6 (20%)
20 "hard"----- 15%

Skarg · 07-12-2019, 11:16 AM

Hmm. I'm so D&D-averse that I don't really have a context for DCC, but it seems to me that it's quite relevant what sort of thing is being checked, and what it takes to get to roll, whether you can re-try and at what cumulative penalty (if any), and whether everyone in a group gets to try, etc.

Also it seems to me that unless this is for something that you want even an unimpressive person to have a decent chance of succeeding the first roll, the scale should go rather higher, up to at least 6d.

xane · 07-12-2019, 04:00 PM

Quote:

Originally Posted by Skarg

the scale should go rather higher, up to at least 6d.

The DC scale probably goes higher, and would start to vary wildly from TFT, but by this stage it seems a bit pointless as most adventure examples will fall in the 10 to 20 range. I just wanted to give an easy conversion for reference, not a total solution.

Bear in mind that the 6+ die skill checks are really there to deter those with no applicable talent, as most would knock one or two die off the check.

Skarg · 07-13-2019, 08:18 PM

I use 6d+ checks also for things that just aren't supposed to be very likely to succeed at all, and/or that should usually resist most attempts, or even repeated attempts or the chance that hundreds should fail. e.g. Things that should likely go unnoticed, feats that should almost surely not work without great luck, etc.

Also some people do get high attributes and/or use Aid spells etc to get high stats. A powerful dragon or wizard may not be all that unlikely to make 6/IQ rolls.

07-12-2019, 05:40 AM	#1
xane Join Date: Jun 2018 Location: London, UK	Difficulty Class Conversion Just some notes on converting Difficulty Class checks, a.k.a. skill checks, from other game systems for use in TFT. I'd be interested on comments or suggestions. The assumptions are: * using average 3d6 attribute scores for a starting character gives a an average of +2 bonus to checks from attribute and class/level bonuses * the TFT success rate is based on an average attribute score of 10-11 typical of a starting 32 point character. DC Rating ---- Success- TFT Equivalent 4 ------------ 95% ---- 2d6 (94%) 5 -"very easy" 90% 6 ------------ 85% ---- 2d6 with -1 (87%) 7 ------------ 80% 8 ------------ 75% ---- 3d6 with +2 (78%) 9 ------------ 70% 10 "easy"----- 65% ---- 3d6 with +1 (68%) 11 ----------- 60% 12 ----------- 55% ---- 3d6 (56%) 13 ----------- 50% 14 ----------- 45% ---- 3d6 with -1 (43%) 15 "medium"--- 40% 16 ----------- 35% 17 ----------- 30% ---- 3d6 with -2 (31%) 18 ----------- 25% 19 ----------- 20% ---- 4d6 (20%) 20 "hard"----- 15% Last edited by xane; 07-12-2019 at 05:52 AM.

07-12-2019, 11:16 AM	#2
Skarg Join Date: May 2015	Re: Difficulty Class Conversion Hmm. I'm so D&D-averse that I don't really have a context for DCC, but it seems to me that it's quite relevant what sort of thing is being checked, and what it takes to get to roll, whether you can re-try and at what cumulative penalty (if any), and whether everyone in a group gets to try, etc. Also it seems to me that unless this is for something that you want even an unimpressive person to have a decent chance of succeeding the first roll, the scale should go rather higher, up to at least 6d.

07-13-2019, 08:18 PM	#4
Skarg Join Date: May 2015	Re: Difficulty Class Conversion I use 6d+ checks also for things that just aren't supposed to be very likely to succeed at all, and/or that should usually resist most attempts, or even repeated attempts or the chance that hundreds should fail. e.g. Things that should likely go unnoticed, feats that should almost surely not work without great luck, etc. Also some people do get high attributes and/or use Aid spells etc to get high stats. A powerful dragon or wizard may not be all that unlikely to make 6/IQ rolls.