Are 3D Printed Dice Fair? How to 3D Print Fair Dice

Creating a fair dice is something that even manufacturers can have trouble with, so how easy would it be to 3D print a set of fair dice? I’d have to say in the real world, you wouldn’t really get a perfectly fair dice because of very small imperfections, so it’s more a question of how fair can we get it.

A 3D printed dice can be significantly fair depending on the type of 3D printing technology you are using. There are imperfections that will affect fairness such as small imperfections on the exterior of the print, as well as the symmetry of the infill of the dice.

This article will attempt to go into detail about fair 3D printed dice, and give a guide on how to create as fair 3D printed dice as possible.

Are 3D Printed Dice Fair?

In the real world, no dice out there is perfectly fair, but they are pretty close to it after rigorous testing and manufacturing techniques.

3D printed dice on the other hand, don’t go through the same strenuous testing or refined creation methods, so I wouldn’t put them against a professional set of dice in any instance. Different printing technologies can improve the fairness though.

I guess it’s down to the criteria of what you call fair really. If your 3D printed dice has 90% accuracy for 1,000 rolls, would you consider that fair? Once you determine what is fair to you, then you can start to determine whether 3D printed dice is fair enough for you.

3D printed dice will be uneven, but to a very small degree if done correctly. With several rolls, you wouldn’t see too much of a difference in the longer term, so it works out just fine for practical purposes.

Post-processing is usually involved to make things look sleak, and polished which can have effects on how fair the dice is.

In terms of value and convenience, store-bought dice are always going to take the cake, but when we are talking about customizability, creativity and a sense of making a cool project, 3D printed dice are a really good option.

People out there have definitely 3D printed dice successfully, whether it’s for D&D and their dice towers, or for board games, they are being used regularly without any issues.

On the other hand, one individual 3D printed a few dice and threw them 100 times each, and he found that they were very far from being fair. He said it could have been due to the infill and its orientation.

There are many factors which go into make a pair of dice fairer, which I will go into detail below.

Things to Consider When 3D Printing Dice

  • Wall Thickness
  • Infill Settings
  • Print Technology
  • Printing Precision & Imperfections
  • Type of Dice

Wall Thickness

The wall thickness is basically the size of the external layers of your model or print. You want to make sure your wall thickness all around your dice is even so there isn’t any weight pushing towards one side, thereby creating an uneven dice.

Many slicers actually make the wall thickness of the base of prints thicker, so keep this in mind when you are deciding which type of die you are going to print.

It won’t usually make a massive difference since the materials you are printing with tend to be lightweight, but it will add to the unfairness of the dice, which we are trying to minimize. You’ll want to be using either PLA or ABS.

You may have to do some tweaks and analyze the layer by layer representation of your prints in the slicing software to get this factor right.

Infill Settings

It may seem like the infill settings is a fairly simple factor since we just want to make it solid with 100% infill, but there are some caveats.

Your slicing software won’t always completely fill in your models, but rather fill the inside with patterns that give stability as well as reducing material and print times. You need to be using a specific pattern that minimizes the instance of this.

An example of this is using the honeycomb infill pattern which creates an infill which goes from bottom to top which gives your die more chance of landing on the bottom of top side.

This usually occurs when you are using an infill pattern which is a non-random fill, so you should use randomized infill patterns which should lead to a more balanced dice.

Print Technology

FDM (Fused Deposition Modeling)

  • Melts and extrudes thermoplastic filament
  • Lower priced option
  • Lower quality and resolution
  • Great for simple prototyping and concept models

SLS (Solid Laser Sintering)

  • Uses a powerful laser to fuse polymer powders
  • Low cost per part as well as high productivity and doesn’t need supports
  • Great mechanical properties
  • Great for functional prototypes and custom manufacturing

SLA (Stereo Lithography)

  • Uses a laser to cure photopolymer resin
  • Good choice of materials to print with
  • Very high accuracy and resolution
  • Great for functional prototyping, patterns, molds and tooling.

This is very similar to SLS but the difference is here you get various colour combinations, and perfect surface. You can reuse the resin as well.

FDM isn’t going to work as well as SLA because of the presence of imperfections and lower accuracy. If you are looking to 3D print the most fair dice you can muster up, I would definitely opt-in for using an SLA or SLS 3D printer.

These used to be very expensive in the past, but an increase in manufacturers and technology have really brought the price down, now in the same price range as FDM printers.

I would recommend going with the Elegoo Mars UV 3D Printer for 3D printing dice.

Printing Precision & Imperfections

You’re going to find the most problems with printing precision and imperfections, unless you have the right equipment behind you.

Trying to get perfectly flat surfaces on an FDM 3D printer is going to be a tough task, especially if you haven’t tuned it well. You’re likely to get bulges on the corners of the die, as well as slight curves around the sides and the top.

You can slightly fix this in your slicing software by decreasing print speed, but it still won’t give you the results you desire.

Some people who have done this decide to add manual support rather than the automated support that is usually implemented. What you can do is configure your slicer to print very thick walls, then post-process the dice with sanding to get them nice and flat.

Type of Dice

Some types of dice are practically speaking, pretty easy to 3D print, while others can be difficult. Dice like the D6 & D4 are going to be fairly easy to get done. When you start moving up to the D8, D12 & D20, you may start running into more issues along the way.

I doubt you’ll get the results you desire after the first print, so do be prepared to have to tinker your settings a few times to get it right.

Although you might think differently, smaller dice are actually tougher to get right because the smaller the object, the more precise it has to be. You have less room for error with a small dice, regardless of how many sides it actually has.

I would opt-in with a large-sized D6 dice to get started, then if you are feeling more adventurous, move onto more complex dice. The hardest ones to print are going to be those small dice with several sides.

Dice that are completely solid from top to bottom are going to bounce around a lot more, so keep this in mind.

Other Things to Consider

Post-processing is probably going to be very useful for you when it comes to 3D printing dice. You can get rid of imperfections like layer lines, ridges and unwanted curves.

If you want to paint your dice, I would use a plastic-safe primer to help the paint adhere to it. Afterwards, it’s a good idea to spray the dice down with a clear-coat sealer in order to protect the outer layers flaking and chipping.

Sometimes using ABS for 3D printed dice is a good option because you can run it through an acetone vapor bath before painting. What this does is smooth out any visible ridges on the outside of your models, so they are smoothed over nicely.

You do need to be cautious when handling acetone, so I would use a tutorial or video guide to get the right tips on how to do this.

How to Check Whether Your Dice is Fair & Balanced

Roll it 100 times, check for evenness of distribution and make sure the average is correct, and then you’re good. It might take a few tries to get it as even as you want, but it’s a cool project to perfect, so you know how to really get that high precision.

It should translate into your future designs and is a good skill to have.

Another method to check whether your dice is fair and balanced is the saltwater trick:

  1. Fill small jar with hot water
  2. Put in two tablespoons of salt, put on the lid and shake it
  3. Put another two tablespoons of salt and shake until most dissolves
  4. Add another two tablespoons of salt, remove the lid, then microwave on high for 30 seconds
  5. Put the lid on and shake until it dissolves, it will be hot so use a dish towel
  6. Once dissolves, set the closest jar in a cold water bath until it cools to room temperature
  7. Put your dice in the water and note where it lands and how it moves

What are Some Good 3D Printed Dice Designs?

This Balanced Dice model on Thingiverse by RarelyEvil is a great design to try out.

Here are the Facets Dice – a Full Set of Custom RPG Dice by sablebadger on Thingiverse.

Cracked RPG Dice Set (D4, D6, D8, D10, D12, D20) on Thingiverse.

You have a Dice Tower by Lau85 on Thingiverse.

Yet another Dice Tower with Fold-Up Trays on Thingiverse.

A D20 Countdown Die (Dice Holder) on Thingiverse.

You can search through Shapeways for awesome 3D printed dice designs that you can purchase in several materials.

There are more designs that you can search through on MyMiniFactory also.

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