Working on a system.

With a d20 you need to roll over an opponents HD + AC - your Combat score.

AC is from 0 to 9 (ascending 0 = no armor)

HD is from 1-20

What range should the combat score be? Right now I have it from 3 to 18.

Goblin 1HD AC5 = 6 vs Combat 3 = 5 or higher to hit
Goblin 1HD AC5 = 6 vs Combat 4 = 4 or higher to hit
Goblin 1HD AC5 = 6 vs Combat 5 = 3 or higher to hit
Goblin 1HD AC5 = 6 vs Combat 6 = 2 or higher to hit

This might work at a low level, but the top range combat scores will make hits automatic on low level monsters. I'm cool with that to a point, but seems like it becomes too easy.

Also any opponent with HD + AC above 22 becomes impossible to hit with a combat score of 3. Is this a problem?


Ancient Dragon 20HD AC9 = 29 vs Combat 10 = 20
Ancient Dragon 20HD AC5 = 29 vs Combat 11 = 19
Ancient Dragon 20HD AC5 = 29 vs Combat 12 = 18
Ancient Dragon 20HD AC5 = 29 vs Combat 13 = 17
Ancient Dragon 20HD AC5 = 29 vs Combat 14 = 16

I've got no problems tweaking the design, but do want it to stay: roll over opponent AC + HD - your combat score.

Thoughts?

I could go with:

Roll D20 (HD+AC-COMBAT).

HD 1-13 and AC from 3-9. This gives me a range of 4-22.

Combat is 3 to 12.

To hit a 22 (HD 13 + AC 9) with a combat of 3 you would need a 20. (22-3=19)

To hit a 22 (HD 13 + AC 9) with a combat of 12 you would need an 11 or higher. (22-12=10)

To hit a 4 (HD 1 + AC 4) with a combat of 3, you would need a 2 or higher. (4-3=1)

With a 12 combat, you automatically hit any monster that is 12 or less (any combination of HD +AC).

Example Scale #1 (total score minus combat):

22-12 = 10 (11 or higher)
22-11 = 9 (12 or higher)
22-10 = 8 (13 or higher)
22-9 = 7 (14 or higher)
22-8 = 6 (15 or higher)
22-7 = 5 (16 or higher)
22-6 = 4 (17 or higher)
22-5 = 3 (18 or higher)
22-4 = 2 (19 or higher)
22-3 = 1 (20)

Example Scale #2 (total score minus combat):

22-12 = 10 (11 or higher)
21-12 = 9 (10 or higher)
20-12 = 8 (9 or higher)
19-12 = 7 (8 or higher)
18-12 = 6 (7 or higher)
17-12 = 5 (6 or higher)
16-12 = 4 (5 or higher)
15-12 = 3 (4 or higher)
14-12 = 2 (3 or higher)
13-12 = 1 (2 or higher)
12-12 = 0 (automatic hit from here below)

Scale Example #3 (total score minus combat):

22-3 = 19 (20)
21-3 = 18 (19 or higher)
20-3 = 17 (18 or higher)
19-3 = 16 (17 or higher)
18-3 = 15 (16 or higher)
17-3 = 14 (15 or higher)
16-3 = 13 (14 or higher)
15-3 = 12 (13 or higher)
14-3 = 11 (12 or higher)
13-3 = 10 (11 or higher)
12-3 = 9 (10 or higher)
11-3 = 8 (9 or higher)
10-3 = 7 (8 or higher)
9-3 = 6 (7 or higher)
8-3 = 5 (6 or higher)
7-3 = 4 (5 or higher)
6-3 = 3 (4 or higher)
5-3 = 2 (3 or higher)
4-3 = 1 (2 or higher)

Quote from: vgunn;903327Working on a system.

With a d20 you need to roll over an opponents HD + AC - your Combat score.

AC is from 0 to 9 (ascending 0 = no armor)

HD is from 1-20

What range should the combat score be? Right now I have it from 3 to 18.

Goblin 1HD AC5 = 6 vs Combat 3 = 5 or higher to hit
Goblin 1HD AC5 = 6 vs Combat 4 = 4 or higher to hit
Goblin 1HD AC5 = 6 vs Combat 5 = 3 or higher to hit
Goblin 1HD AC5 = 6 vs Combat 6 = 2 or higher to hit

Just a quick note on the numbers 6 - 3 = 3, so should be 4 or greater to hit, right? Or am I missing something?

Regarding the too easy to hit question. It's only too easy to hit if you get to attack first (win initiative). You can thus allow the player to bleed off attack benefit for speed. Any -1 to hit converts as a +1 to initiative, or you can make it more challenging by requiring a -2 to to-hit for each +1 initiative. An extra attack may also be allowed by say a -3 penalty. So when attacking easy targets (goblins) as a master swordsman the player can get to attack an additional goblin at -3 a second additional goblin at -6 a third additional goblin at -9 and so forth. So a fighter with 3 attacks per round can get to attack its sixth goblin at -9 which with a 2 or better to hit converts to 11 or better which is still pretty doable.

minor variation to simplify the math.  I'd go with 1D20+Combat Score > HD + AC

It avoid the subtraction, easier to do and makes the combat score into a "bonus" which is psychologically more pleasing.

Quote from: Xanther;903425minor variation to simplify the math.  I'd go with 1D20+Combat Score > HD + AC

It avoid the subtraction, easier to do and makes the combat score into a "bonus" which is psychologically more pleasing.

Thanks!

Quote from: Saurondor;903406Just a quick note on the numbers 6 - 3 = 3, so should be 4 or greater to hit, right? Or am I missing something?

You are right, messed that up.

What are you trying to achieve / simulate?

What do you want your mechanic to achieve at the table than the basic D20 mechanic does not?

Quote from: Spinachcat;903469What are you trying to achieve / simulate?

What do you want your mechanic to achieve at the table than the basic D20 mechanic does not?

Don't get this too why they try to invent the wheel.

Quote from: Spinachcat;903469What are you trying to achieve / simulate?

What do you want your mechanic to achieve at the table than the basic D20 mechanic does not?

Less modifiers is one of the goals.

Seems like (1D20 + Combat Score > HD + AC) is pretty simple.

Why the minimum cap on 'Combat' score of 3?

Also > or = is usually easier to remember than just >, otherwise you are working out a target number and then adding 1 for the 'true target number'. Reduce combat score by 1 to eliminate the issue

If you are worried about an unhittable total from AC + HD of 22 you could run with the ever popular 20 is always a hit.

Before I can answer the question of a given value being "too easy" or not there is some basic information required to come to an informed opinion.

What exactly is the effect of a "hit? Hitting easily might not be a big deal depending on the HP/wound system or it might be the whole ball game!  Without knowing what landing a typical hit means in the system its hard to say if hitting ever gets too easy.

Quote from: Exploderwizard;903758Before I can answer the question of a given value being "too easy" or not there is some basic information required to come to an informed opinion.

What exactly is the effect of a "hit? Hitting easily might not be a big deal depending on the HP/wound system or it might be the whole ball game!  Without knowing what landing a typical hit means in the system its hard to say if hitting ever gets too easy.

Well said.  A good way to look at it, how many hits to kill do you want.  Some might like super deadly, 1 hit = 1 kill, others where hits represent more attrition, many hits to kill.  There is no replacement for just testing it.  Running some mock combats and see how it plays out.  I've found people tend to like the attrition model, as when there is a "hit" something is happening.  The danger is combats can go on forever.