Ideal RPG/Wargame Dice (D12 on D60)

Ideal RPG/Wargame Dice

Each time you need to roll "one more than before", it becomes more difficult by the same factor (133%), approximately.

Great for sensible difficulty increases in RPGs and Wargames that use a lot of Die Modifiers (+/- DMs)

Can be used in game design to eliminate complicated rules, extra tables, and mental arithmetics. Also great as a drop-in replacement for a D12 or 2D6.

Includes OpenSCAD source files in case you'd like to modify the design.

Based on

• pmoews' D60: https://www.thingiverse.com/thing:1045263
• my own intuitive D20: https://www.thingiverse.com/thing:2811944

Printing

Printing with an FDM/FFF printer, I recommend printing two separate halves and glueing them together with super glue.

The files include two halves with two registering holes to ensure proper aligment.

Use a 8 mm length of 1.75 mm diameter filament in each of the registering holes for assembly.

Probabilities

The Ideal Dice feature the following distribution:

1: 15x
2: 11x
3: 9x
4: 6x
5: 5x
6: 3x
7: 3x
8: 2x
9: 2x
10: 1x
11: 1x
12: 2x

The chances of achieving a certain number or higher are:

1: 100% :-)
2: 75%
3: 57%
4: 42%
5: 32%
6: 23%
7: 18%
8: 13%
9: 10%
10: 6.7%
11: 5.0%
12: 3.3%

The chances of success for each increase of +1 are reduced to the following percentage of the unmodified chances:

1 + 1: 75%
2 + 1: 76%
3 + 1: 74%
4 + 1: 76%
5 + 1: 74%
6 + 1: 79%
7 + 1: 73%
8 + 1: 75%
9 + 1: 67%
10 + 1: 75%
*11 + 1: 67%

So the die is not perfect, due to only having a finite number of faces, but I think it's pretty good :-)
History

I came up with this die out of frustration with convention die roll modification systems back in the late 1980s, calling it the "logarithmic die". Attempts to build such a die by modifying existing D20 dies resulted in ugly, stickered, poorly-rolling creations so that I gave up on the concept.

My hopes that someone else would have the same idea and come up with a nice mass-produced die of this type unfortunately never materialized.

With the advent 3D printing, it suddenly became easy to have good-looking and accurate dice printed, so I designed D20 dice in FreeCAD, which came out great.

As the D20 only delivers numbers from 1 to 7, I kept looking for a bigger die that would give a greater range of numbers, and when I found pmoews' D60, that was just perfect for the purpose as it can be used to give a range of 1 to 12, just what many games need.

So, here's the ideal logarithmic D60 for you! :-)