3D dice results are not random

[Weissrolf]

I did 3x 1 mio. D8 rolls and they all showed the same pattern with very little variation. Currently I do not plan to do another mio. D20. 3D click-/auto-rolling is bad and my energy currently goes into finding better workarounds (after fixing the Instant Dice extension to make it usable).

Auto-rolls and click-rolls should not be using 3D dice, because they lack the random mouse-movement seed. And even then I am not convinced that this isn't more of a physics engine problem than random seed problem.

Best solution would be to update FGU to a more modern version of LUA, which introduced better RNG (random.new, later also implemented in math.random).

[Jiminimonka]

I did 3x 1 mio. D8 rolls and they all showed the same pattern with very little variation. Currently I do not plan to do another mio. D20. 3D click-/auto-rolling is bad and my energy currently goes into finding better workarounds (after fixing the Instant Dice extension to make it usable).

Auto-rolls and click-rolls should not be using 3D dice, because they lack the random mouse-movement seed. And even then I am not convinced that this isn't more of a physics engine problem than random seed problem.

Best solution would be to update FGU to a more modern version of LUA, which introduced better RNG (random.new, later also implemented in math.random).

In your opinion.

[Weissrolf]

You are stating the obvious here.

Integrating a new version of LUA could introduce compatibility issues if any old functions were deprecated. LUA v5.1 was introduced 2006 and ended 2012.

[Weissrolf]

I found pure Lua implementations of three different random number generators. Unfortunately I cannot implement them, because FG's Lua API excludes "setmetatable" which is used by said implementation.

Next I may compare FGC's 3D dice results with FGU's, because they do roll visibly different.

We do have some plans to tweak the dice rolling behaviors to have a little more rotational velocity to look better, but changing the underlying system is not in our plans.

I specifically wonder how can having "a little more rotational velocity" only make it look better? Should that not also change the possible outcome? Currently 3D hardly ever turn, often only just before they settle. Sometimes they don't even turn when they hit the table several times. So more rotation should surely change that?

[Weissrolf]

FYI: 3D dice fail the PractRand randomness test with 8 KB test sequences (range of numbers tested), on my W10 system Instant Dice fails with a 128 KB test sequence. Both are small and testament to how bad these RNGs are, but the latter at least survives larger test sequences than the former.

[Weissrolf]

Instant Dice, 1 mio. rolls, distribution of D20 results:

#6: 5.05%
vs.
#7: 4.98%

There are 1.8% more #6 than #7 results (50453 vs. 49631).

FG Classic, 1 mio. rolls, distribution of D20 results:

#2: 5.21%
vs.
#10: 4.80%

There are 8.6% more #2 than #10 results (52099 vs. 48002).



FG Unity in direct comparison:



There are 18.8% more #16 than #1 results (54863 vs. 46177).

[Weissrolf]

Distribution of Doubles (2 dice consecutively showing the same result) in percent (expected value ~0.25% per die side):



In terms of DnD5E "advantage" rolls this means: Your chance of rolling another 3 after an initial 3 are 33% higher than rolling another 1 after an initial 1. And on average your chances of rolling a double 3 are 16.5% higher than they should be.

For comparison:

[Jiminimonka]

I want to see the dice table have different surface qualities and possible coffee stains, both sugary and non-sugary and see how the dice interact on those surfaces and while we are at it add VR dice and possible table shake.

[Trenloe]

I want to see the dice table have different surface qualities and possible coffee stains, both sugary and non-sugary and see how the dice interact on those surfaces and while we are at it add VR dice and possible table shake.

If you don't have anything constructive to contribute then please don't post anything. Please leave this thread to those who are interested in this type of theoretical stuff.

[Weissrolf]

I want to see the dice table have different surface qualities and possible coffee stains, both sugary and non-sugary and see how the dice interact on those surfaces and while we are at it add VR dice and possible table shake.

This would be a nice touch (pun intended), but only useful if the initial click-/automation-roll is anywhere close to how users roll dice via mouse-movement. And even then the physics engine needs to be good enough to not just blur everything into much too deterministic paths (literally).