It seems like 99% of roleplayers use the round-edged dice produced by the major dice manufacturers. These dice have rounded edges because they are dipped in paint and then tumbled. This wears the surface off of the dipped dice, smoothing the edges and leaving paint only in the numbers. Tumbling does not wear the surface of the dice evenly, however; it results in the dice taking on an irregular egg-shape. These egg-shaped dice produce a non-random distribution of roll outcomes. Gamblers call these "cheater dice". Most gamers call these "Chessex" or "Games Workshop" dice. I have one Chessex d20 that is so bad that it looks like an egg-shaped marble.
Is it fair to ask players not to use their crappy Chessex dice? I mean, if they feel that one of their dipped-n-tumbled dice is "lucky", it probably DOES have biased outcomes. Isn't this cheating?
I always bring a pile of precision-edged GameScience and casino dice to the games I run. I hand out sets to all the players. Yet some players - especially gamers at conventions - insist on using their own dice. The only other gamers I've seen using precision dice are the hardcore old school roleplayers. Why is this? It seems like if someone is obsessive enough to learn how to play a game with 576 pages of rules, they might spend a few minutes thinking about how their dice function.
This is kind of an academic question, of course. I would never kick off a session asking someone to tuck away their favorite "lucky" dice. This decreases joy. I guess I am just ranting here because I am surprised by how many people who fancy themselves as serious gamers use shit-ball dice. I am even more surprised that most game shops don't carry, or even know about, precision polyhedrals.
The thing I am most surprised by, though, is that every second of my life has lead up to this moment where I actually sat down and wrote a nerd-rage blog post about rounded vs. sharp edged 20-sided dice. Sigh...
Rant over. Thanks for stopping by!
NOTE: I wrote this post assuming it was made clear to everyone years ago that Chessex and GW dice are extremely inaccurate. Some of the comments suggest that many people still think the inaccuracies of these dice are insignificant. I direct you to this 2006 experimental study from an engineering class at ASU on Chessex and GW d6s. On average they are over 12% off.