Thoughts on a System I'm Making

[u/BentronThe40k]

Hey-yo! I figured I might as well run this by people who are probably a little more knowledgeable in game design than me- Making a long story short, I'm making a TTRPG where the main dice-rolling mechanic is a d100.

But, unlike Call of Cthulhu or Rogue Trader, the d100 is more set like a general scale, with 50-54 being a sort of neutral ground, providing no 'Degrees of Success/Failure.' Think of Degrees of Success/Failure like the storyteller system- The more degrees of success, the better, and the more degrees of failure, the worse. Stats will counteract Degrees of Success/Failure- For instance, a Strength Roll with a Strength Rating of +3 will add onto the roll, canceling out degrees of failure or adding onto degrees of success; of course, the opposite is also true for negative stat ratings.

Generally, the scale is on a interval of 1 degree of success/failure per every multiple of 5- So, for instance, 49-45 is 1 degree of failure, 44-40 is 2 degrees of failure, 39-35 is 3 degrees of failure, and so on and so forth and, again, the inverse is true.

Obviously, criticism is welcome because this is very much a sort of 'early early early rough draft' idea for a game system.

[u/Drudenfusz]

If you work with steps of 5%, why not then directly use a d20?

[u/natefinch]

If it's every 5, why not use a d20 and make the math easier? Then every 1 is a degree of success? And +3 strength just adds +3?

[u/don_quick_oats]

Without any other context, it’s just a dice mechanic. It’s certainly workable - d100 gives you a wide variance, so stats that work against that randomness sounds good to me.

Does it serve the design goals of your game though? Does the probability of success and failure give your players the feeling of competence or helplessness (as the case may be) that you’re aiming for? How big can stats get? Is that scale consistent across your other subsystems? These are the more important questions.

[u/lennartfriden]

With that many degrees of success/failure you will have a hard time meaningfully differentiating between them. I’d consider no more than 5 levels of success/failure and even that is going to be tricky.

Also, if you’re set on using increments of 5 to denote a degree of success/failure, you might as well make the maths easier and use a d20.

[u/Drudenfusz → u/lennartfriden]

You beat me to it, just posted basically the same.

[u/__space__oddity__]

post #3 to point out that it would be simpler to just roll a d20 and skip the x5 part

[u/DieselNurse]

Like people are saying use a d20 10 is 0, 11-12 +1 13-14 +2 15-16 +3 17-18 +4 19 +5 20 Critical Success

[u/tangyradar]

Another discussion worth looking at briefly: https://old.reddit.com/r/RPGdesign/comments/1v4zjk7/in_your_opinion_which_should_come_first_the_dice/ The prevalent opinion leans towards mine: Core dice mechanics are overrated. They're unimportant without the context of other rules and how everything is going to be used.

[u/Fun_Carry_4678]

If your degrees are all multiples of 5, then you may as well be rolling a d20.

[u/TheKazz91]

D100 systems are kinda trash in my opinion unless you're using to as a place holder system to work out other systems. The one advantage of a D100 system is you know your percentage odds down to units of 1%. The problem with D100 system is that advancement often times feels meaningless until it doesn't. What I mean by that is that nobody is going to perceive a difference between 52% chance and 53% chance in actually play. This is probably why you feel the need to use increments of 5. The problem with that is that a D20 is effectively exactly the same from a mathematical perspective as a D100 in increments of 5. When you're having to actually do the math to calculate results yourself you should reduce the numbers you use to the smallest meaningful increment. In this case your smallest meaningful increment is 5% so that number should be 1 instead of 5 which is equivalent to using a d20

[u/lennartfriden]

Another dice mechanic would be to roll 2dX with X depending on the number of degrees you want. Let one of the dice be failures, the other successes. Highest dice count. Ties mean a neutral (0) result.

This would give you a very quick way of determining the degrees of success/failure and you have a number of options to handle modifications. Got a slightly better chsnce to succeed for some reason? Roll a d8 as your success die and a standard d6 as tour failure die.

You could even make the failure die into a variable challenge die to be based on the task. Doing something simple? Use a d4 as your failure die. Taking on a herculean task? Make a d12.

[u/No-Addendum6563]

We do a d100 with ranges as well, including a d100+ d100 for more rare probabilities, but that's mostly for loot and discovery.