I'm starting to think through the combat and skills systems for my game, which will feature any number of bonuses a player or NPC may have to affect their chances of success. I want advancement in my game to be open ended, meaning there is no level, nor skill, cap. As such, rather than these bonuses getting added to the result of a random 1-100 number, I'm thinking about having them adjust the range. So, rather than success being calculated like this: 37 (Random 1 to 100 value) + 10 (elf racial bonus) + 20 (weapon bonus) + 20 (greater weapon blessing) >= 45 (creature's defense) I might do something like this: 65 (Random 1 to 150 (100 (base probability) + 10 (elf racial bonus)) + 20 (weapon bonus) + 20 (greater weapon blessing) value) >= 45 (creature's defense rating) So a player may receive a limitless amount of bonuses from their level, skills, race, temporary enhancements, etc., and they will always aid the player, but they never hit the cap of automatic success. It also introduces a natural diminishing return, as the difference between 100 and 110 is significant, but the difference between 500 and 510 is much less so. And it also allows for a variety of bonuses, most will add to the upper range for success, but some of the rarer ones will add to the lower range (20-100 means you can't fail for attempts with a rating of 20 and below), or even rarer bonuses that do, indeed, add to the random result. So what do you guys think? Are systems like these used, and are they desirable? Are my mathematical assumptions all correct? Are there potential problems I've overlooked? EDIT: I had to use the word "plus". The symbol wouldn't show up when I previewed. What's up with that? [Edited by - CyberSlag5k on March 12, 2009 2:04:15 PM]

Quote:Original post by CyberSlag5k
EDIT: I had to use the word "plus". The symbol wouldn't show up when I previewed. What's up with that?

Just a bug in the preview - they display fine in the post itself.

Quote:Original post by swiftcoder

Quote:Original post by CyberSlag5k
EDIT: I had to use the word "plus". The symbol wouldn't show up when I previewed. What's up with that?

Just a bug in the preview - they display fine in the post itself.

So they do. Thanks.

Thanks, Kylotan.

Quote:Original post by Kylotan
It's always good to look at the minimum effect, maximum effect, and average effect of any change to a system to see how it would work. eg. With a system where you are increasing the random range rather than increasing a bonus to a fixed range, the increase of any given number is lessened. In your new system, a +10 can mean nothing at worst, +10 at best, and on average is +5 to your result. So you may need to double the size of the bonuses you give out compared to the previous system, to give the same sort of effect.

Yeah, I'd considered, actually, how the lower bounds should move as well. It's probably not going to come into effect all that often, but if a character gains a bonus to the lower bound, he's gauranteed to succeed at lower requirement tasks. I thought about having skills increase the upper bounds with every rank, and the lower bounds with every 10 ranks, so at skill rank 1 your chances are 1-101, at rank 10 your chances are 2-110, at rank 100 you're at 10-199, and at 300 you're at 30-299.

So if the skill in question affects your chance to hit (and for simplicity's sake, let's say it's the only thing that affects it), at rank 300 you're gauranteed to hit a sewer rat with a defense of 30, practically gauranteed to hit a goblin with a defense of 60, very likely to hit a troll with a defense of 100, and you've got a shot at a stone golem with a defense of 280. I rather like that, but it might be difficult to balance.

Quote:
One issue you may find is that whereas the first system makes it possible to guarantee success against weak opponents, the second doesn't, and that chance of failure remains throughout the range of opponent competence. So top level characters will still have a chance of failing to hit a rat (whereas presumably the rat won't be able to hit them).

I kind of like that, too. There's always the chance of a super powerful player missing the weakest creature in the game. The player might be distracted or make an, albeit unlikely, mistake, or the creature might get lucky and just happen to move the right way. Maybe I don't want to move that lower bounds. I'm not sure yet.

Quote:
Another thought is that you've not addressed here how the defence score is calculated, and obviously the formula can't be balanced without knowing all the inputs. Attack scores come from a range while defence scores seem to be fixed. This means that, depending on whether they grow proportionally or equally as player competence increases, you may find the chance of landing a hit drops off almost to nothing at higher levels. Again, the min/max/avg is how to look at this problem - calculate reasonable values for low level characters, high level characters, and a typical 'average' level character, and look at the way the stats will work for them.

Actually, I'd thought about the defensive side working the same way as the offensive, which is to say it'll affect the random bounds. Maybe to hit you have to get a 100 or greater, so with no weapon and no skill, you've got a 1% chance of hitting, with a basic weapon and low skill, you've got a 15% chance of hitting, and with a great weapon and great skill you've got a 90% chance of hitting. Now factor in the creature's defensive rating, which swings the thing the other way.

So, our elf cleric above has a to-hit rating of 50, but the goblin's defense is 45, so the random roll is now 1-105, meaning there's about a 5% chance to hit. But the problem with that is if the defensive rating is greater than the offensive rating, it's impossible to hit the creature, so obviously that needs some work, too.