Tuesday, May 31, 2016

Slimline Gear Grid for Small Build Plates

Slimline Gear Grid for Small Build Plates: locked and loaded.
I just published my original design for a slimline gear grid.

The grid is meant to be printed on 3D printers with smaller build plates and requires some simple assembly.

If you would like to download the design, print one and assemble it, you can download the STL from Thingiverse.

Alternately, you can find it on Tinkercad, if that's where you do your modeling and printing.

Hit the jump break for some reflections on my process and some additional ideas about how to assemble and use the grid: normal Manager updates will resume shortly!

Background and Inspiration

Clockwise from top: empty grid, grid ready for assembly and
loaded grid.
I got a 3D printer for my birthday and, in order to teach myself how to use it, I spent most of Memorial Day weekend 2016 working on building a better mousetrap.

Personally, I ditched the in-box card stock gear grids as soon as a better option became available.

Close-up/tilt-shift glamor shot.
Between the generally high amount of cards that are on the table during all phases of play and the dice-chucking that goes on during showdowns, my experience of the card stock grids is that as soon as you've got four (or more) players sitting in front of 36 gear cards laid out on four pieces of card stock, you're going to have a lot of chaos.

Which is to say, if you're playing a lot of KD:M, swapping out the card stock grids for something that keeps all of those little square cards from flopping around is practically mandatory.

And so, as soon as they became available for purchase, I bought eight of the 3D-printed, heavy-duty gear grids designed by Fddlstyx (you can still buy them here).

I have been playing with the grids for months and, inspired by their design and the iterative process behind their creation, I decided to make a gear grid of my own, but to take the design in a different conceptual direction.

Design Goals

Version 3d in Tinkercad.
Specifically, I gave my self the job of accomplishing two goals:

  1. develop a design that can be printed in a single shot on a smaller build plate.
  2. use the smallest amount of filament possible when printing the grid.
I should mention here that I am an absolute novice at this and my design is far from perfect, but I iterated on it for a while and I feel like it meets its goals fairly efficiently.

In terms of software tools, I used Tinkercad to create my design and I used ReplicatorG to 3D print, i.e. "build" it. 

Both are free tools.

I went through three major design iterations before I landed on a design I liked (and those three iterations had their own distinct, significant, milestone sub-versions). 

From start to finish, I probably spent something like three or four days' worth of man-hours learning how to do this stuff and refactoring my design.

Small Build Plate Friendly

The build plate on my Creator Pro is about 6" x 9".

So, as much as I like the heavy-duty, square-base "platform" design that I have been using, I could not simply download and print the Fiddlstyx design: the base was about two inches wider than my printer's base plate.

ReplicatorG and Tinkercad in Windows 10, which still uses
literally the worst/lamest screen-capture software possible.
My original thought was to download the file and "remix" it. The term "remix" is the not-quite-right jargon supplied by Thingiverse to describe the process of downloading someone else's design, modifying it, and then re-sharing it as your own.

My remix idea was to cut the big-base design in half and then do it as a two-shot build.

I tried this and, while my remix wasn't a total failure, joining the two pieces together was a total failure. My first idea for "joint" pieces was a figure-a-into-slot-b kind of design that my printer just didn't have the resolution to pull off.

At the end of these experiments, I decided that I wanted to create my own design that was created, from the ground-up, to be printed by machines with smaller build plates.

Furthermore, I decided that doing multiple prints wasn't optimal for a lot of reasons: joining pieces together seems unavoidable (given the small plate design constraint), but executing multiple print jobs makes the process of producing a functional grid a major pain in the ass.

I decided that my final design had to be a one-shot build, even on my small build plate.

Slimline Design

The second goal of my design emerged during my first iterations.

Essentially, I set out to come up with a gear grid that I could build in one shot on my small build plate and, while I was working on that design, I realized that a slimline design is a.) something that doesn't already exist and b.) a design with better material efficiency.

Which, to put that another way, is to say that I set out to replicate the Fddlstyx design and then realized, as I was working on making it modular and one-shot-printable, I realized that I wasn't married to the idea of a big, square base type of form factor.

Rather, it occurred to me that it would be an interesting design challenge to try to deliver a minimalist, slimline design. 

The point of this was to not reinvent the wheel: the big-base design is already out there and more than sufficient. 

Rather, I decided that if I was going to roll my own, I wanted to create a substantially different option from the big base design, which, in my opinion, is basically the de facto gold standard.

And, as the saying goes, if it ain't broke...

Iteration and Design Process

My first draft--call it version 1--was not far from the Fddlstyx design. Rather than a single, square base, it was a square base with circles cut in the middle of the cells, for easy card removal.
One of my original, Fddlstyx-inspired, two-shot designs.
The transition from version 1's platform to version 2's rings.
The general idea is that it was a flat sheet that was printed in thirds--a sort of triptych--that was then assembled. 

Version 1 had some pretty serious design problems. Super-glueing the folds of the triptych together was messy (the seams were tough to match up properly) and, more annoyingly, the only way to print this design was to do it in two prints.

At about 30-50 minutes a print, this was a major barrier to convenience.

Another thing that bothered me about version 1 is how much filament it used. And not so much because filament is expensive or anything, but more because printing that big square platform is kind of a time-sink and it doesn't really do much but lend the grid some heft and structure, if you think about it.

Which, to put that another way, is to say that having the platform is nice, for stability, but the grid ultimately just lays on the table and doesn't really need to move around or be picked up or anything like that.

At that point, it occurred to me that I was under no real obligation to stick with the "platform" design that I nicked from Fddlstyx, and I decided to ditch the platform structure for a design that used rings as the main structural element of the gear grid. 

Version 2

Version 2a, printed and assembled.
At any rate, version 1 became version 2 when I abandoned the square platform and turned the circles cut into the centers of the square cells into a ring-based support structure.

The big idea of version 2 was to print nine 55mm circles with brackets for the cards in three rows and then assemble those.

The overall outcome wasn't terrible--I actually think it looks kind of cool--but again, assembly was kind of a problem: the idea behind locking the rows together was to use overlapping flaps and glueing these together made for uneven seams. 

Also, as with the version 1 design, version 2 required multiple prints and required printing a lot of parts that weren't strictly necessary for accomplishing the basic goal of keeping gear cards from moving around during play.

That was about the time that I realized that version 2 was about to fork: what I had in my hand was version 2a.

And so I refactored version 2, with its triptych columns of three vertically-arranged grids, to what I came to refer to as version 2b: version 2b moves from a three column or triptych print to a two column, diptych print with a six-grid "trunk" and a three-grid "stem".

Version 2b: two prints, i.e. a "trunk" of six
grids and a "stem" of three grids. 
This version also started to remove unnecessary connections between the brackets that hold the cards. One result of this was that the design/shape of the printed and assembled unit started to look really avant-garde: part of it resembled a "cloverleaf" style highway on-ramp and the other part looked like a sort of basic F1-type race track. 

At some point during version 2b iterations, I also realized that the printed and assembled grids would need to be stackable, so version 2b was the first to include 5x5mm cubes in strategic positions, intended to bear the weight of stacked grids and to protect the card brackets from being damaged during stacking.

Ultimately, version 2b was an interesting experiment, but it still could not be printed in a single shot on my small build plate, so I had to back off of that design and make some changes.

Version 2c moved back to the triptych design and was was the first design that could be printed in a single shot. 

The big idea was that I took the minimalism principle of version 2b and broke it into three pieces: a diagonal row of three grids formed the "trunk" and two "stem" pieces consisting of three, triangularly oriented squares that would then be glued onto the "trunk" during assembly.
Version 2c, printed and assembled. Sweet Tribal, brah.
In version 2c, the stacking support cubes were centralized and reduced: I realized, while working with version 2b, that I didn't really need four cubes: the design is light and the four cube support design was total overkill.

One major problem of version 2c was the connector pieces, i.e. where the two "stem" pieces are affixed to the "trunk". The problem was flimsiness, basically: the design is slimline, so the assembled unit didn't need to be a tank, but, by the same token, having it crack apart during storage or transport is kind of a deal breaker.

As I was tooling around with version 2c, I realized also that the ring-based support structure meant that I was printing more material that I had to print, strictly speaking. I was kicking around some doodles, and the structural lines of version 2c gave me the idea for an "external" support ring structure.

The main idea behind external ring structure, as opposed to an internal ring structure, was that I could print less and have even slimmer lines.

Version 3

Version 3a laid over the original design sketch for version 3.
Since version 1, I had been designing the grid for sleeved cards, which means that the grid cells themselves are larger than the actual cards they hold. One of the first problems with version 3a was that the external rings didn't support the cards fully and they could slip under their supports.

Version 3b, therefore, adds triangular supports to the upper and right card-holding brackets.

I liked 3b and, when I started writing this post, I meant to put it forward as the final version. But then I had this idea about how I could streamline it and make it stronger at the same time.

Version 3c, the concept that never was.
Version 3c never ended up getting printed, however, because it was too wide by about half an inch. I lost several hours trying to design it and make it work, but in the end, the footprint of the design was just never going to be narrow enough to fit my build plate.

3c was probably my favorite design, in terms of appearance, and I think if I take up this kind of design project again, I would probably use it as my jumping-off point.

Left: version 3b. Right: the first prototype build of version 3d.
Version 3d (har har), then, was a return to 3b that solved some of the major issues of verison 3b. 

Notable improvements between 3b and 3d include the arrow-shaped supports in grids that would otherwise be too large for sleeveless cards and the inversion of some of the structural supports (specifically the ones in the corners, where I would have had to used arrow-shaped supports, but instead was able to kill two birds with one stone and use a structural ring to support the card). 

The most important structural change is the addition of the circular bars under the central grid, which replace the single structural support bar in the lower-right grid of 3b.

Finally, if you count all three versions and their various sub-versions, I went through about eight distinct designs. 

Design evolution: versions 1 through 3, left to right.

Assembly and Finishing

I don't expect a lot of people to download and print my design, but if you do, here are a few notes on assembly and finishing, i.e. priming, painting and varnishing for actual use.

In my printing (and the image at the top of this point), I used a cheap ABS filament that costs about $15 a spool on Amazon. Some of my prints are in white and some are in red, but both are the same filament.

The black grids in this post and in Thingiverse are ones I primed and varnished.

It probably wasn't strictly necessary, but I decided to degrease grids that I ended up priming: I did this by toothbrushing them with dawn. 

Once scrubbed, I primed them with the matte black Army Painter spray primer. I varnished them in Testors Dull Cote (which is great stuff: it's pricey, but it is the best matte spray varnish you can buy, in my opinion). 

Assembly. Left to right: printed, ready for assembly and assembled.

Thanks for looking!

If you have any ideas/questions/comments, use the comments or hit me up on Thingiverse!


  1. This is brilliant Tim. I went for a wholy different approach, still using cardboard but adding some coin sleeves (dunno how the con collecters sleeves are called) to secure the gear cards in place. Your last desigh looks awesome and if I had a 3d printer I'd totally get this for my group (either printed black or painted black, though). Also I completely appreciate the effort of designing a lightweight grid (first: less usage of fillament is always a plus, second: its not like our fav. game wasn't heavy enough already, right?!).
    Long story short: Great job, and thanks for the insights in your thought process. Really interesting. Kudos :-)

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