The 3D - 4D - 5D Heresy

[bactram1]

Die rolls in TFT are based on bell curves, usually 3D6. But when the going gets tough, you don’t adjust the result of the die rolls, instead you just roll more dice. The bell curve for 4 dice is much higher than 3 dice. The average roll on 3D6 is 10.5, and an adjusted skill level of 10 will succeed 50% of the time. But on 4 dice that changes to 15.9%. That seems like excessively harsh. If you go to 5 dice the chance of success if your skill level is 10 is 3.24%.

Now, when SJ lost the rights to TFT, he started working on the Great Unnamed Role Playing System (AKA GURPS, I remember the great reveal that changed “Great Unnamed” to “Great Universal”). At this time SJ changed to using 3D6 for all rolls, and adjusted the results by +1, -2, or something. Still keeping an adjusted skill level of 10, 3D6 is still 50%. Adding 1 to the die results (an adjusted skill level of 9) gives 37.5%, +2 gives 25.93%, and +3 gives 16.2%. These odds seem more reasonable. It’s almost as if SJ was using experience from TFT to the design of GURPS.

Now that SJGames bought the rights to TFT, reviving a beloved game from my youth, we’re back to adding dice. While it’s easy enough to house-rule 4D6 to 3D6+1 and 5D6 to 3D6+2, I’d like to see something official on this. I think it’s just too much for 50% odds to change to 15.9%. I know that SJ will probably be against this, which is why I’m calling it a heresy. SJGames could have a PDF that says: If the GM wants to change the odds of very hard feats he may want to change 4D to 3D6+2, and 5D to 3D6+3. There can be tables showing the effect this would have.

What do you think?

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I got the percentages from https://anydice.com/program/9350