captchemo

Wow, that turned out awesome! Great to hear you're making with your son. I started with my son about the same age. He's a livelong Maker now!

I made the dice and printed them. Ran 100 rolls and they fit almost perfectly in the curve! I'll get the 'Ible edited and add the files and images as soon as I can. Again, thanks for the idea. I know I've now beat this horse about as dead as I can get it, but I was thinking....what about a 16 sided stick dice with the number layout of the 16 side spin dice I did. Might print a 16 sided cylinder and see if it rolls well. Might be too "roll-y" but at this point, what's one more die!

Dude! That's a great idea. It took me a sec to figure out what you meant, but after laying out all the possibilities of that, it fits perfectly. One chance of 0 & 4, 4 chances of 1 & 3, and 6 chances of getting a 2. I think I'll try and make one and will add to the files above if it works! Again, thank you for exploring this concept with me, it's been a lot of fun.

I should disclose and just realized, the pawn STL I included is from the thingiverse file I reference in the text above from @cymon, not of my creation.....sorry about that.

Holy cow, why didn't I think of that.... That's a really good point, and I think it would improve the randomness. I did include a version without numbers, so you could always just print your own numbers. Great observation, thanks!

So I've been working on the challenge and have it mostly done. Interesting results, so I'm writing another Instructable to document it properly. Hopefully have it up in a day or so. Thanks for the motivation!On the weighted spinner, I was able to distribute the weights around so it actually spun pretty nicely....results, not so much.

Ok, now I get it. I did have to have my son simplify it a bit! ( he just took a probability and statistics class...) and you're right, the odds aren't truly random in Ur, that's what makes it challenging.So with that as a baseline, I see two ways of making a spinning dice that is "equal" in odds to the 4 binary dice normally used. #1 is to make a 16 sided single top (no need to make a double like the percentile) and put 1- 0, 4-1s, 6-2s, 4-3s and 1-4 on it like you suggested. I don't think it would matter on placement around the circle if we assume the 16 sided spin dice is equally random for each facet.#2 would be to make a weighted 5 sided dice that gives you the same odds. I did a rough calculation and since 2 is the highest odds at 6 out of 16 chance that would be basel…

Ok, now I get it. I did have to have my son simplify it a bit! ( he just took a probability and statistics class...) and you're right, the odds aren't truly random in Ur, that's what makes it challenging.So with that as a baseline, I see two ways of making a spinning dice that is "equal" in odds to the 4 binary dice normally used. #1 is to make a 16 sided single top (no need to make a double like the percentile) and put 1- 0, 4-1s, 6-2s, 4-3s and 1-4 on it like you suggested. I don't think it would matter on placement around the circle if we assume the 16 sided spin dice is equally random for each facet.#2 would be to make a weighted 5 sided dice that gives you the same odds. I did a rough calculation and since 2 is the highest odds at 6 out of 16 chance that would be baseline at 100% weight of a side, then 0 & 4 would have 1 in 16 chance so by running the proportions those sides would need to be 16.66% of weight of the 2 side. One would have 1 in 4 chance to would be 66.6% the weight of side 2. I thought it would be easier to calculate it by volume, to take the volume of the #2 side at 100 and reduce the others by their percentages keeping the dice with equal shaped sides and facets, just take out the volume required instead of making different shaped side/facets which wouldn't make it as fair landing on the smaller sides I would think. This would be a much more difficult way of designing it but would be interested in seeing if I could pull it off!So, challenge accepted! I'll start playing with both options and see if I can successfully print them. Then I'll spin them and see what kind of odds I can get from them. Cool! Another project to work on....

Interesting concept. How did you come up with the number odds? Not doubting them, just curious. Is it from the originally found 4 - 4 sided dice that a lot of the current remakes use? This is basically 4 bi-numeric (?) dice or for the 4 sided dice with 2 sides marked and 2 not marked. You roll 4 dice and roll is the count of marks up. Making a multi-sided dice with multiple numbers present representing their odds is interesting. Be fun to make one and roll the odds to see how they play out.

So glad you like the nerdy Step 3! It was very edited down from I originally had. I almost didn't put it at all, but I think that section is such a big part of the project. Not everything goes the way you plan. I'm a firm believer of owning your mistakes and issues. It's the only way we grow.For your 1st question, best way to answer is to watch the video with sound on. The inner die does nest down and lock into place. It's the same faceted bottom as the inner facets on the main die. When it's spinning its immobile, but once the spin breaks and the main die starts bouncing about (on those facets) it throws up the inner die and it's momentum continues it's spin until the facets stop it's motion too. I kept widening the hole of the inner die until I felt it was large enough to allo…

So glad you like the nerdy Step 3! It was very edited down from I originally had. I almost didn't put it at all, but I think that section is such a big part of the project. Not everything goes the way you plan. I'm a firm believer of owning your mistakes and issues. It's the only way we grow.For your 1st question, best way to answer is to watch the video with sound on. The inner die does nest down and lock into place. It's the same faceted bottom as the inner facets on the main die. When it's spinning its immobile, but once the spin breaks and the main die starts bouncing about (on those facets) it throws up the inner die and it's momentum continues it's spin until the facets stop it's motion too. I kept widening the hole of the inner die until I felt it was large enough to allow for free bouncing!On 2, that's exactly how I was going to redo the dice! Once I realized it needed to print face down, I wanted to print the face and stem separately, mostly to get a better print of the numbers. That's why I designed the original dice with a 45 deg bevel to it would print on it's side and get the best surface for the facets and the numbers. I couldn't figure out an easily printed way of matching the top and bottom so just left it as is. You could draw out and print a "face plate" in paper with nice numbers and design then glue it on..?If you always print the main and inner dice up to where the numbers print, then switch filament colors for the rest or just a few layers in a contrasting color for the numbers to show better. I've done this before (on nicer printers...) and it really makes a design pop.thanks, for the comments, really appreciate the dialog! patrick

Wow, great suggestions. This is kind of what I meant by how far down the rabbit hole you want to go! Yes, to make it properly, balancing it for spin is the correct method. What I "assumed" was that the real randomness occurs after the dice slows enough to hit the sides. The facets then would randomly bounce the unit as it's rotational momentum kept it in motion until gravity takes over. And that there would be enough bouncing to put it more or less on the same playing field as a regular dice bouncing on a table.I tried to focus on the symmetrical balance of the piece as much as possible. You can see the difference numbers vs. no numbers showed in the graphs. I only embedded the numbers .04 in. and they are fairly close in area to each other. I didn't have the means of ta…

Wow, great suggestions. This is kind of what I meant by how far down the rabbit hole you want to go! Yes, to make it properly, balancing it for spin is the correct method. What I "assumed" was that the real randomness occurs after the dice slows enough to hit the sides. The facets then would randomly bounce the unit as it's rotational momentum kept it in motion until gravity takes over. And that there would be enough bouncing to put it more or less on the same playing field as a regular dice bouncing on a table.I tried to focus on the symmetrical balance of the piece as much as possible. You can see the difference numbers vs. no numbers showed in the graphs. I only embedded the numbers .04 in. and they are fairly close in area to each other. I didn't have the means of taking it further as for as precision balancing.What do you mean by heterodyne oscillation? I had to Google that!! I'll have to ask my son, he's studying EE and is taking a class right now on radio frequencies. I think there is some oscillation difference going on. I think that is would helps randomize the inner die. Anyway, thank you very much for the comments and suggestions. It would be awesome to machine this from aluminum and see how tight you could make it!

That's for the comment. If I was in the market for a 3D printer now (which I kind of am...just gotta get the wife to be as well!) I would get the Prusa Mk3. I think it's the best printer on the market right now, period. That being said, you really can't go wrong with the Creality printers. I haven't used one, but for less than $400 and with everything I've seen and read these are the best printers to start with. Simple machines, cheap, awesome fidelity, and open software/slicers. If you don't like it or use it as much as you thought, you're not out that much money. Yeah, the parts are cheap, and things might not last as long as more expensive units, but its a very inexpensive way to see if you like the hobby. The Prusa is $1200 (which is still just over half what I paid for my Mak…

That's for the comment. If I was in the market for a 3D printer now (which I kind of am...just gotta get the wife to be as well!) I would get the Prusa Mk3. I think it's the best printer on the market right now, period. That being said, you really can't go wrong with the Creality printers. I haven't used one, but for less than $400 and with everything I've seen and read these are the best printers to start with. Simple machines, cheap, awesome fidelity, and open software/slicers. If you don't like it or use it as much as you thought, you're not out that much money. Yeah, the parts are cheap, and things might not last as long as more expensive units, but its a very inexpensive way to see if you like the hobby. The Prusa is $1200 (which is still just over half what I paid for my Makerbot Rep 1 in 2012) so it's still "cheap" compared to the high end printers like Ultimaker and Makerbot, but you really aren't getting much if any benefits or better results by spending twice enough for these two. Sorry, don't get me started.... This is just my opinion, your mileage may vary. Good luck!

Yeah, for sure. Out of town at the moment but will try and add it when I get home. Think I can edit an 'ible once its uploaded..

Thanks Alex! Really appreciate it. It was a fun project and very enlightening learning about fair dice and randomness.

Depending on the age, these would be perfect for homeschoolers! I originally made these for a summer camp at the museum I work at. The kids loved them. With all the pieces cut out, it should be an easy build. The teachers made shields and pool noodle horses for them and they paraded around the museum one day. For the horses, they just bent over about a foot of one end and duct taped it to the body. Add googly eyes and reins and you're set!One fun add on I had was feather plumes for the top. The camp teachers didn't get nice big feathers, but some of the kids liked them. Cut out a couple of disks (round if possible) about 1" diameter of cardboard with a hole in the center. The feathers then poke thru the disks and the top of the helmet. The disks help support the feathers. …

Depending on the age, these would be perfect for homeschoolers! I originally made these for a summer camp at the museum I work at. The kids loved them. With all the pieces cut out, it should be an easy build. The teachers made shields and pool noodle horses for them and they paraded around the museum one day. For the horses, they just bent over about a foot of one end and duct taped it to the body. Add googly eyes and reins and you're set!One fun add on I had was feather plumes for the top. The camp teachers didn't get nice big feathers, but some of the kids liked them. Cut out a couple of disks (round if possible) about 1" diameter of cardboard with a hole in the center. The feathers then poke thru the disks and the top of the helmet. The disks help support the feathers. Hot glue it all together.I would definitely tape over the brads on the inside. I originally didn't do this and everyone was catching their hair on them. There's lots of cool samples of medieval helmets on line that could give the kids authentic examples to see for different ventilation options.Good luck, and let me know how it goes!Patrick

I like your helmet design! I had not seen that before. On the laser, it is very easy to burn cardboard and paper. There are two ways to control how "strong" the laser cuts through a material. You can adjust the speed and power of the laser, turning them up or down depending on what you are cutting. I usually leave the power on full and adjust the speed at which it cuts (for most materials except thin cardboard or paper). This way, I'm only adjusting one variable. It sounds like your project was cut with too high of power or too slow of a speed. This will result in charred or burnt material. Hope this helps!

Wow, never would of thought of that...not sure if they would crush cardboard. I guess it depends on how sharp they are. Definitely worth a try! Thanks for the suggestion.