Category Archives: 3D models

The Thingiverse “Heart Gears” Phenomenon – A Physible Family Tree

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Last September, I wrote over at MAKE about the Thingiverse “Cube Gears” phenomenon, briefly tracing the origin of user emmett’s Screwless Cube Gears through its evolution from Haruki Nakamura’s papercraft geared heart sculpture via user GregFrost’s printable Broken Heart thing. At the time, I really wanted to exhaust the graph of the cube gears / heart gears phenomenon, but didn’t have the available free time. I’ve had some good publishing experiences using Graphviz to generate directed graphs, before, and kept dreaming about using it to show the family tree of Thingiverse physibles descended from Broken Heart. Well, I finally got around to doing it. These data were mostly gathered manually, but Thingiverse is already tracking derivation information for things, and it would not be a great coding challenge to automate the generation of these types of graphs using Graphviz, which is free software. The SVG version, above, should be fully clickable so you can navigate to the various things as you please. If you can’t see it, for whatever reasons, there is a standalone SVG version here, and a large (non clickable) image here.

Here’s the Graphviz source:

digraph tverse_heart_gears {
graph [fontname="Helvetica",  fontsize=12, fontcolor=lightgray, bgcolor=white, tooltip="REMOVE THIS PHRASE"]; 

/* SVG tooltips are a PITA and require post-processing the SVG output to eliminate tooltips where you don't want them, e.g. over the whole background of the graph.  "REMOVE THIS PHRASE" just makes it easier to find manually. */

edge [penwidth=0.7, color="#1989FF", arrowsize=0.5];
node [shape=box, margin="0,0", penwidth=1, color="gray", label="", fontname="Helvetica", fontsize=8, fontcolor="#1989FF"];

915 [tooltip="Companion Cube by Gianteye", image="915.png", URL="http://www.thingiverse.com/thing:915"];
1614 [tooltip="Weighted Storage Cube (from Portal) by cyrozap", image="1614.png", URL="http://www.thingiverse.com/thing:1614"];
3219 [tooltip="Stellated octahedron by Wootfish", image="3219.png", URL="http://www.thingiverse.com/thing:3219"];
3575 [tooltip="Parametric Involute Bevel and Spur Gears by GregFrost", image="3575.png",  URL="http://www.thingiverse.com/thing:3575"];
4683 [tooltip="Broken Heart by GregFrost", image="4683.png",  URL="http://www.thingiverse.com/thing:4683"];
6073 [tooltip="Cube Gears by emmett", image="6073.png", URL="http://www.thingiverse.com/thing:6073"];
6190 [tooltip="Exploitable Heart by emmett", image="6190.png", URL="http://www.thingiverse.com/thing:6190"];
6291 [tooltip="Heart Gears by emmett", image="6291.png", URL="http://www.thingiverse.com/thing:6291"];
6336 [tooltip="Heart Gears on a Plate by JadeKnight", image="6336.png", URL="http://www.thingiverse.com/thing:6336"];
6375 [tooltip="Weighted Storage Cube Gears by whosawhatsis", image="6375.png", URL="http://www.thingiverse.com/thing:6375"];
6499 [tooltip="Eccentric Sphere Gears by whosawhatsis", image="6499.png", URL="http://www.thingiverse.com/thing:6499"]; 
6533 [tooltip="Gear gears by whosawhatsis", image="6533.png", URL="http://www.thingiverse.com/thing:6533"];
8581 [tooltip="Portal Companion Cube by grimm", image="8581.png", URL="http://www.thingiverse.com/thing:8581"];
9104 [tooltip="The head of Stephen Colbert by Colbert", image="9104.png", URL="http://www.thingiverse.com/thing:9104"];
9148 [tooltip="Colbert Head Gears by emmett", image="9148.png", URL="http://www.thingiverse.com/thing:9148"];
9194 [tooltip="Sun Gears by 67restomodder", image="9194.png", URL="http://www.thingiverse.com/thing:9194"];
10288 [tooltip="Pin Connectors by tbuser", image="10288.png", URL="http://www.thingiverse.com/thing:10288"];
10483 [tooltip="Screwless Cube Gears by emmett", image="10483.png",  URL="http://www.thingiverse.com/thing:10483"];
10493 [tooltip="Portal Companion Cube w/hearts by CarryTheWhat", image="10493.png", URL="http://www.thingiverse.com/thing:10493"];
10541 [tooltip="Pin Connectors V2 by tbuser", image="10541.png", URL="http://www.thingiverse.com/thing:10541"];
11253 [tooltip="Motorized Cube Gears by dougc314",  image="11253.png", URL="http://www.thingiverse.com/thing:11253"];
11660 [tooltip="Two Color World by m6mafia", image="11660.png", URL="http://www.thingiverse.com/thing:11660"];
12208 [tooltip="Screwless Heart Gears by emmett", image="12208.png", URL="http://www.thingiverse.com/thing:12208"];
14070 [tooltip="Earth Shot by WilliamAAdams", image="14070.png", URL="http://www.thingiverse.com/thing:14070"];
16442 [tooltip="MOTORIZED screwless heart gears! by Zh4x0r", image="16442.png", URL="http://www.thingiverse.com/thing:16442"];
16893 [tooltip="Keychain Screwless Heart Gears by Zh4x0r", image="16893.png", URL="http://www.thingiverse.com/thing:16893"];
16909 [tooltip="Big Love <3 - Heart Gears by faberdasher",  image="16909.png", URL="http://www.thingiverse.com/thing:16909"];
17336 [tooltip="Textured Earth by bld", image="17336.png", URL="http://www.thingiverse.com/thing:17336"];
17713 [tooltip="Earth Gears by bld", image="17713.png", URL="http://www.thingiverse.com/thing:17713"];
18061 [tooltip="Stellated Octahedron Gears by Lemon_Major", image="18061.png", URL="http://www.thingiverse.com/thing:18061"];
18134 [tooltip="Screwless Heart Gear Replicator Plates by IWorkInPixels", image="18134.png", URL="http://www.thingiverse.com/thing:18134"];
18144 [tooltip="Screwless Heart Gears - Plated by toybuilder",  image="18144.png", URL="http://www.thingiverse.com/thing:18144"];
22069 [tooltip="Gear Heart with Handle by catzpaw164",  image="22069.png", URL="http://www.thingiverse.com/thing:22069"];
23237 [tooltip="Screwless Companion Cube Gears by LocheMage", image="23237.png", URL="http://www.thingiverse.com/thing:23237"];

subgraph cluster_gregfrost {
	style="rounded,filled";
	color=lightgray;
	3575 -> 4683;
}

subgraph cluster_bld {
	style="rounded,filled";
	color=lightgray;
	17336 -> 17713;
}

subgraph cluster_tbuser {
	style="rounded,filled";
	color=lightgray;
	10288 -> 10541;
}

subgraph cluster_Zh4x0r {
	style="rounded,filled";
	color=lightgray;
	16442;
	16893;
	}

subgraph cluster_emmett {
	style="rounded,filled";
	color=lightgray;
	6073 -> 10483;
	6073 -> 6291 ;
	6190 -> 6291;
	6291 -> 12208;
	6291 -> 9148;
}

subgraph cluster_whosawhatsis {
	style="rounded,filled";
	color=lightgray;
	6375 -> 6499 -> 6533;
}

8581 -> 10493;
10493 -> 23237;
915 -> 1614;
4683 -> 6073;
4683 -> 6190;
/* 3575 -> 6073;  redundant derivations pruned */
6073 -> 6375;
/* 6073 -> 6499; redundant derivations pruned */
1614 -> 6375;
/* 10288 -> 10483; redundant derivations pruned */
10541 -> 10483;
10483 -> 11253;
10483 -> 12208;
6291 -> 9194;
6533 -> 9194;
9104 -> 9148;
6291 -> 6336;
12208 -> 22069;
12208 -> 18144;
12208 -> 18134;
12208 -> 18061;
12208 -> 17713;
14070 -> 17336;
11660 -> 17336;
12208 -> 16909;
12208 -> 16893;
12208 -> 16442;
12208 -> 23237;
3219 -> 18061;
}

These data were gathered on 2012-06-06 and are already obsolete, I should note. The graph has new nodes since then.

My first 3D print

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This is the first full print off my MakerGear Mosaic FFF 3D printer. A shot glass is the traditional “maiden” print among RepRappers—it’s a quick, simple object and the libation-tightness of the finished print is a pretty good test/demonstration of the printer’s abilities. In fact, the traditional file is minimug.stl, which I elected to forego in favor of this slightly larger and more impressive shot glass, which is Thing #11944 from user raldrich. It is teardrop-shaped in honor of the RepRap project logo. It was printed from red 1.75mm polylactic acid (PLA) filament on the evening of Tuesday, January 17, at a small party my friends and I had to celebrate the event. We each independently verified its Glenfiddich-tightness. The traditional playing of Daft Punk’s Human After All album, during the printing, was also observed. The rhytmic, protomusical whines of the Cartesian robot’s stepper motors are a good complement to most Daft Punk songs.

My Gömböc model, and controversy surrounding same

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A couple of years back a commenter on one of my Shapeways models suggested I should attempt to reverse-engineer the Gömböc (Wikipedia). I was interested in the challenge and undertook to do so. Like most of my projects, it proved to be vastly more work than I anticipated, and after several iterations of my model I became preoccupied with other matters. Recently I was e-mailed by an interested reader who wondered what became of that effort, and I went back and found my latest model and offered to e-mail it to him if he was interested. He agreed, and I decided that I might as well just post the model on Thingiverse and make it available to anybody else who might want to see it in the future.

The process of reverse-engineering began by using AutoDesk Photo Scene Editor on a series of 360-degree images of the original Gömböc published on the Gömböc website. This software lets you define common reference points on an object between images taken from different angles, and extrapolates the shape of the object using the resulting vector field. It yielded a crude Gömböc model which I then used as the basis for an eyeballed CSG model.

It isn’t perfect, and it probably won’t actually work as a Gömböc, either, because the original shape is reported to be very sensitive to dimensional tolerances. But I spent quite a bit of time and energy on this and thought somebody might use it as a starting point for improvements. Or better yet, that it would persuade the Gömböc discoverers that it is time to finally publish the details of the commercial Gömböc’s shape in the open literature.

In fact, shortly after posting the model, I received an e-mail from Prof. Gábor Domokos, one of the Gömböc’s co-creators. Prof. Domokos politely took issue with some of the statements I originally made in the model’s description. My original statement has been modified in response to his comments. It may change again if our discussion continues.

To the best of my ability to research the question and understand what I’ve read, the Gömböc discoverers, though advancing the claim that the shape popularized and commercialized as the Gömböc is a meaningful scientific discovery, have not actually published that shape for purposes of peer review. Two years ago when I undertook this project, I exhausted the available published resources on the subject, including all the authors’ papers on the Gömböc and related topics and the Hungarian IP filings that protect the Gömböc shape for commercial purposes in Hungary.

Since that time the Gömböc shape has received a U.S. design patent (#D614077). The patent document includes line art that constitutes the best and most specific public description of the commercial Gömböc shape that I have seen. It still does not satisfy the standards of scientific peer review as I understand them.

Domokos and Péter Várkonyi claim to have produced a shape that has unique mathematical properties, but they have not told the world exactly what that shape is, so their claim for this particular shape cannot be verified. They will, however, sell you an expensive CNC-machined copy of that shape.

I am no mathematician, and though I believe their published works establish to the standards of that community that mono-monostatic bodies exist, I am not satisfied that their claim of that property in the shape publicized and commercialized as the Gömböc is supported by sufficient evidence. Unless they publish exact parameters of the commercialized Gömböc shape in the open literature, their claim that it is really mono-monostatic cannot be verified by other researchers, and hence must remain open to doubt.

Prof. Domokos has politely requested that I remove the posted 3D model. I have respectfully declined to do so, as I do not believe it violates any of their established legal rights, and I believe it may have actual value for researchers interested in the Gömböc and mono-monostatic bodies in general.