Rolling for Non-Weapon Proficiencies and Skills

I did a lot over the Labor Day weekend. I didn't have much time to write. However, I kept battling a preoccupation with NWP and Skills in Andras. Having a roll-under d20 mechanic meant inventing an arbitrary starting point. I didn't want NWP and Skills to start with high scores because there was nowhere to go.

I had this vision of a Mage having a 17 Spellcraft at 2nd level. The problem? A 2nd level Mage being able to identify a large number of spells when he/she has two in their personal spell book. Over time, this Mage can only gain two more ranks in Spellcraft.

I could assign a lot of modifiers, but I don't want to make a modifier table for every NWP and Skill if I can help it. I could return to the slot-purchase method that is more true to 2e.

I briefly considered a roll-over mechanic and setting DC scores. But I do not want a d20 or 3e mechanic if I can help it. Nothing wrong with it, but the feel changes from something almost like 2e into something very much like 3e.

Looking at some things in my collection, I found a 2d12 roll-under mechanic. It is a great system, but alas, not OGL or Creative Commons.

Then it hit me on Sunday, but I didn't have a chance to write it down until now. I kept mulling a d20+d10 roll-under mechanic. It feels less like 2e, but doesn't feel like 3e. Will I keep it? I don't know yet.

Here's some math behind a d20+d10 mechanic:

  • There are 200 different die rolls.
  • The bell curve is actually a long plateau.
  • Using ability scores, even an 18 ability score only gives you a 62.5 percent chance of success.
Roll Roll <=
2 0.50%
3 1.50%
4 3.00%
5 5.00%
6 7.50%
7 10.50%
8 14.00%
9 18.00%
10 22.50%
11 27.50%
12 32.50%
13 37.50%
14 42.50%
15 47.50%
16 52.50%
17 57.50%
18 62.50%
19 67.50%
20 72.50%
21 77.50%
22 82.00%
23 86.00%
24 89.50%
25 92.50%
26 95.00%
27 97.00%
28 98.50%
29 99.50%
30 100.00%

In thinking about Theives' Skills, this mechanic allows me to set Climb Walls at DEX for a 1st level character. In 2e, the character starts with a 60% chance of success and can increase that ability up to 90% at first level. Starting with DEX and allowing a character to go up 6 ranks only does the same thing if the Rogue has an 18 DEX. I like that a lot. Speaking of Theives' Skills, d20+d10 also allows me to set values very close to OSRIC percentages for success for NPCs.

This mechanic also enhances my ongoing struggle with creating a skill-based Mage. The skill to cast a spell starts with INT and increases by INT Bonus at every level. So, for an INT 16 Arcanist, they begin with a Spellcasting Skill of 16 and increase by 2 at every level.

In doing the numbers, this also simplifies the modifiers based on spell level. An Arcanist casting a 1st level spell has no modifier. A 2nd level spell has a -5 modifier to Spellcasting Skill. A 3rd level spell is -10 and so on. So much simpler! In looking at creating spells using the OpenD6 system, it is also possible to create 0 level spells. They would have a +5 bonus to Spellcasting skill.

With 0 level spells, this mechanic also allows for a little bit of house magic by NPCs. Assuming an INT of 12, an NPC would have a better than 50/50 chance of casting a 0th level spell. Considering the minimal effect, this is enough to make things interesting without severe unbalancing.

The effects of 0th level spells would include things like divining one answer to a yes/no question, fists do 1d3 lethal damage for one round, divining the last image seen before death from a fresh corpse, a oen time +3 skill bonus for one usage of a Thief skill, etc. All of these effects are dependent on a lengthy casting time and verbal, somatic and material components. Without these four things, the effects are more comparable to 1st and 2nd level spells.

Lots of options are still available, but it's food for thought. You have any thoughts?

Odd Mechanic

I was working on a random way to give my kids some very simple addition subtraction problems. I will admit that I am thinking a bit far in the future as we really haven't covered subtraction yet.

That being said, I am a fan of the d4-ized d6 featured at the Dice Creator store. I am saving up for one of these. I love the possibilities that come the fact that it has more than one number on its face.

When I first saw it, I realized that it could make a great randomizer simply by concatenating the numbers rolled. Last night, though, I had some crazy idea to combine the d4ized-d6 with a Fudge die and an LCR die. (It kept me awake for half the night.) The Fudge die would tell you to subtract, concatenate, or add. The LCR die would tell you what other number on the face to compute with. For example, if you rolled a 6 (meaning that the 6 is on the bottom), the Center number would be the upside-down 1 above the 6. The Left and Right numbers would vary, but let's say for the sake of argument that the Left number is a 2 and the Right number is a 5. Left+Add would produce 8. Right+Add would produce 11. Center+Add makes 7. Left+Subtract gives you 4, Center+Subtract gives you 5, Right+Subtract produces 1. Left+Concatenate makes 62. Center+Concatenate makes 61 and Right+Concatenate makes 65.

You get the idea.

Yes, you can get negative numbers. The range produced goes from -5 to 65. Believe it or not, the median roll is a 7. In a roll-under system, the chances of rolling a 7 or less are about 55%.

Here is the spreadsheet with my analysis.

If, by some odd stretch, someone decided to use this mechanic in a roll-under system. It does allow for a natural "diminishing returns" feature.

Say for example that a system has a skill system rated by points. A Skill score of zero still gives you a 16% chance of success. Once you get up to a 7, you have a better than 50-50 chance of success. You're above a seventy precent chance of success at 15. After that, though, it's slow going to get a lot of progress. You break an 80% chance of success at a score of 34. To get above a 90% chance happens at a skill score of 52.

Critical successes? Roll a -4 or -5. Critical Failure? 61 or better.

Would this work in an RPG? Maybe not. It requires some getting used to. I think it might be better for a sports simulation sim, like American Footbal, for example. These kind of fiddly rolls happened in Paydirt. The results can emulate all kinds of tables, like Second Season Football. (I own both of these, by the way.)

Anyway, there's my odd mechanic idea that kept me awake last night. Enjoy!