attribute modifier vs/or xd6 rolls

[sekalo]

I just found The Fantasy Trip and noticed that some of the older documentation and rules have two forms of dice roll modifications.

option (A)
-# DX/IQ or ST


option (B)
xd6 (example 4/IQ)

What was the purpose to combine these mechanics? I have looked at the probability of the 3d6 with modifiers vs 4d6. It appears that 4d6 is +/- probability of having a -2 Attribute modifier.

In addition, I noticed that most of the skills modifications use Option B. Where the combat rolls use Option A. Only thing I can think of is that Option
B changes the bell curve.

I play a very rules light 1d6 home brew system, but wanted to add some 'lite' tactical combat. I am unsure to use GURPS and strip out what I don't want. Or use The Fantasy Trip - most Melee and Advance Melee rules with some Wizard.

Thank you

[hcobb]

Subtracting dice reduces the chance for a critical failure and makes some tasks automatic.

Adding dice greatly increases the chance of a critical failure.

For example:

DX 13 quarterstaff user attempts to disarm DX 12 swordsperson: DX 13 -4 = 9, a 37.5% chance to hit the weapon followed by a 26% chance to fail to retain: Final success ratio 9.75% and if you fail thou shall be run through. While the same swordsperson attacking a mere dagger expert doing a defend has adjDX 12 -1 / 5d for a 5.88% chance to hit and a 9.8% chance of disarming themselves. So the dagger is slightly better at disarming and much better at defense.

If a task only has a big attribute adjustment then you can hope to brute force it by taking an extremely high attribute level (DX 15 Flinger, or IQ 17 goblin wizard say), while if multiple dice are added then you really need a helper with that talent.

[sekalo]

Originally Posted by hcobb

Subtracting dice reduces the chance for a critical failure and makes some tasks automatic.

Adding dice greatly increases the chance of a critical failure.

For example:

DX 13 quarterstaff user attempts to disarm DX 12 swordsperson: DX 13 -4 = 9, a 37.5% chance to hit the weapon followed by a 26% chance to fail to retain: Final success ratio 9.75% and if you fail thou shall be run through. While the same swordsperson attacking a mere dagger expert doing a defend has adjDX 12 -1 / 5d for a 5.88% chance to hit and a 9.8% chance of disarming themselves. So the dagger is slightly better at disarming and much better at defense.

If a task only has a big attribute adjustment then you can hope to brute force it by taking an extremely high attribute level (DX 15 Flinger, or IQ 17 goblin wizard say), while if multiple dice are added then you really need a helper with that talent.

What do you find works better for something quick and fast play but still allows for tactical hex grid placement and tactics?

[TippetsTX]

The author never made the reasoning for these two approaches explicit, but my own interpretation is this...

Adding dice has the effect of increasing the impact of random chance on the outcome... more dice means more variation. Modifiers to rolls (which are fixed values) reduce the impact of 'randomness' in either a positive or negative way.

Therefore, if you want to increase the difficulty of a task you should first ask if it is harder due to factors outside of anyone's direct control (and add extra dice) or if the outcome is more influenced by measurable factors like skills.

I like having both the fine-grained, incremental modifiers as well as the broader adjustments to the 'degree of difficulty'. It creates an interesting nuance between something you have and something that is.

[hcobb]

Originally Posted by sekalo

What do you find works better for something quick and fast play but still allows for tactical hex grid placement and tactics?

TFT combat is mostly DX modifiers (negatives for range and cover, positives for backstabs, etc.) while the noncombat rolls are mostly dice adjustments (Alertness + Naturalist vs Slime, etc.)

[sekalo]

Originally Posted by TippetsTX

The author never made the reasoning for these two approaches explicit, but my own interpretation is this...

Adding dice has the effect of increasing the impact of random chance on the outcome... more dice means more variation. Modifiers to rolls (which are fixed values) reduce the impact of 'randomness' in either a positive or negative way.

Therefore, if you want to increase the difficulty of a task you should first ask if it is harder due to factors outside of anyone's direct control (and add extra dice) or if the outcome is more influenced by measurable factors like skills.

I like having both the fine-grained, incremental modifiers as well as the broader adjustments to the 'degree of difficulty'. It creates an interesting nuance between something you have and something that is.

"random chance" but 4d6 still create a bell/pyramid dice curve with 14- as the average. However, more combination and steps in the curve over 3d6. This is why I am confused, since 10- is 50% average on 3d6 and 14- is the 50% average on 4d6. However, the 4d6 does give a 18+ as 15/16% so is it safe to say that when you want something to fail bad for the player you would use 4d6 since critical failure is higher on the 4d6 vs 3d6?

[sekalo]

Originally Posted by hcobb

TFT combat is mostly DX modifiers (negatives for range and cover, positives for backstabs, etc.) while the noncombat rolls are mostly dice adjustments (Alertness + Naturalist vs Slime, etc.)

HI 'hcobb' yes, I did notice that trend where noncombat skills use the dice adjustment, which further confused me on the two mechanics.

[sekalo]

I am coming from a rpg background of: Classic Traveller, Battletech/mechwarrior 1e, WEG Star Wars d6 1e and D&D B/X.

So I was sort of excited to find GURPS and TFT since i have a weakness for d6 games.

[TippetsTX]

Originally Posted by sekalo

"...so is it safe to say that when you want something to fail bad for the player you would use 4d6 since critical failure is higher on the 4d6 vs 3d6?

ITL pg 9 defines the thresholds for critical success/failure for each possible die-count.

1 Die: Automatic success, always, on a 1-die saving roll.
2 Dice: 2 = automatic success; 12 = critical failure
3 Dice: 5 and below = success; 16 and up = failure
4 Dice: 8 and below = success; 20 and up = failure
5 Dice: 11 and below = success; 22 and up = failure
6 Dice: 14 and below = success; 24 and up = failure
7 Dice: 17 and below = success; 26 and up = failure
8 Dice: 20 and below = success; 28 and up = failure

[sekalo]

Originally Posted by TippetsTX

ITL pg 9 defines the thresholds for critical success/failure for each possible die-count.

1 Die: Automatic success, always, on a 1-die saving roll.
2 Dice: 2 = automatic success; 12 = critical failure
3 Dice: 5 and below = success; 16 and up = failure
4 Dice: 8 and below = success; 20 and up = failure
5 Dice: 11 and below = success; 22 and up = failure
6 Dice: 14 and below = success; 24 and up = failure
7 Dice: 17 and below = success; 26 and up = failure
8 Dice: 20 and below = success; 28 and up = failure

I do not have ITL, and I would not expect the crit success would change. By moving the crit target number, is keeping the same % inline with 3d6. 5- is 4.62 on 3d6. 8- 5.40%. For the crit failure on 4d6 is roughly the same percentage compared to 3d6. That is what i find so confusing.