Tag Archives: voronoi

I Can’t Print This On My Replicator


Fused deposition modeling (or fused filament fabrication, if you want to avoid a nastygram from the legal eagles at Stratasys) is the process by which Makerbot Replicators, Afinia H-Series printers, Cubify Cube 3Ds, Repraps, Rostocks, and too many homebrew printbots to enumerate turn STL files from electrons into objects.

In FDM/FFF printing, the device lays down a layer of melted plastic, moves its build platform downward a tiny bit, and then repeats the process until the model’s completely built.

I’ve had my Replicator 1 for about a year now and I think it’s safe to say that I’ve put it through its paces. I’m pretty good at 3D printing with this particular FDM printer. I understand and work around its limitations, paying close attention to the 45-degree rule. FDM printers generally can’t print too large an overhang from one layer to the next; gravity interferes and the print fails with often hilarious results.

A few months ago I designed a model that I knew had no real hope of ever printing on an FDM printer. I wanted to see what Shapeways was capable of printing for under 20 bucks, so I built a Voronoi Seej bloxen and sent it over to them. A few days later this showed up in the mail:


You’re welcome to give it a shot yourself: just download the model. I’d be interested to see your results.

A cutaway view demonstrates why the Voronoi bloxen fails on an FDM printer. Most of the model’s OK, but it violates the 45-degree rule in a big way right at the top of the block.


The print at the top of the post was my first try at printing this bloxen on my Replicator. Those tiny Voronoi cells on the bottom of the model make it really hard to keep the bloxen on the platform. If any one of those little filament loops should detach from the platform, it’ll eventually get caught on the print head and catch another loop, and another, and another, and once your model is touched by His Noodly Appendage, it’s done for. Ramen.

Those little loops need to stick fast to the HBP So it’s back to FDM Printing 101: using a raft.

After a new slice, the Replicator had no problem keeping the base of the bloxen on the build platform.


A few minutes later it looks like the Voronoi pattern is holding up well. The mortises on the bottom of the bloxen are printing just fine. I’m starting to think this print might just succeed…


…aaaaand the 45-degree rule rules its ugly head and the print starts to fail as predicted right at the top of the bloxen.


As fails go, this one isn’t spectacular. Enough filament fell into the gaps to provide a scaffold for the top layers. The bloxen is still a fairly solid print, certainly usable in a Seej match.


So. Another failed print. But there’s still hope for those of us who haven’t been able to secure $30 million in venture capital funding. I’ve been corresponding with Dean Piper, inventor of the mUVe 1 printer. Dean took up the challenge of printing the Voronoi bloxen, and his resin-based printer knocked it out of the park:


I feel like home 3D printing is in the VHS vs. Beta stage of its history. On one side we’ve got superior market penetration of FDM printers, but resin-based machines like the mUVe are going to be the bots to watch in the next few months.

Erk. Almost forgot: this post is the latest in my continuing one-man crusade to make “Voronoi” the word of the year for 2013.

Make Shroom For Daddy

fungus_token

Here be the follow-up to last week’s spore counter. Once you get enough spores built up on a thallid, players can place a saproling on the battlefield.

I’m still tweaking my fungus deck, but I find having a half dozen or so around during a game is handy so I can use them as puppets and make them shriek glub squeek glub rwarrrr! while they swarm over my kids’ creatures en masse. Adds a lot to the game.

If you’ve got your own printer, you too can help spread fungus across the land. You can download the model here. You could use this guy anwywhere you need a 3D model of a semisentient fungus: D&D, MTG, or on your dashboard.

I’ll print you as many as you need at my Etsy Store.

This model is distributed under the Attribution-ShareAlike 3.0 US license. Please remix and enjoy.

Magic: The Gathering Spore Counter

cat_token

Here’s the second in my series of Magic: The Gathering tokens. This one’s not so much a token but a counter.

It’s a spore! Highly useful for decks that incorporate a lot of fungus, like mine. A dozen of these will fit in your pocket or dice bag with ease.

I’ve a bunch of Thallids, so every three turns or so I get a new saproling token on the field.

A Meekstone keeps the kids’ bigger critters from being too much of a threat while my horde pulsates and grows.

If you’ve got your own printer, you too can help spread fungus across the land. You can download the model here.

You’ll need a lot of these if you’re going with the full-on fungus deck. I can print you as many as you need at my Etsy Store.

Here’s what it looks like from above. There’s a saproling germinating in there.

cat_token

Astute readers may surmise what the next model is going to be.

This model is distributed under the Attribution-ShareAlike 3.0 US license. Please remix and enjoy.

Joining the Voronoi Cargo Cult

WTF is a cargo cult?

If you are like me, you do not want to become an expert in Meshlab. You do not really care about learning the interface, because you’ve already learned fifty other interfaces and you do not want to be an expert in every Tom-Dick-and-Harry Open Source 3D application.

You want an easy-to-follow, step-by-step, hand-holding process that pretty much guarantees you a Voronoi surface.

You want to join the Voronoi cargo cult.

Voronizing isn’t rocket science, but other tutorials I have seen online have skipped one crucial step that makes it all but impossible for cargo cultists like me to get a Voronized surface out of Meshlab. I beat my head against the wall for hours until I stumbled upon the solution.

Now that my bruises have yellowed and my rage has mellowed, I’ve written my own tutorial at the Voronoi-bloxen inspired request of Seej player, maker, and all around nice guy AndyP.

Ok, here we go.

Step 1: Download, install, and launch Meshlab. It’s free. I’m running Meshlab 1.3.2 on OSX, but I imagine the UI will be mostly the same no matter what OS you’re on.

Step 2: We’re going to Voronize a sphere. Go to Filters->Create New Mesh Layer->Sphere.

Sphere! Woot.

The process of Voronizing involves creating lots of vertices on the target mesh and then creating some voodoo connection between them to make the Voronoi pattern. So first we need more vertices on the sphere.

Step 3: Go to Filters->Remeshing, Simplification, and Reconstruction->Subdivision Surfaces: Loop. I just accepted the defaults. When it’s done, you’ll see that the default sphere looks a lot smoother.

Step 4: Sampling the new vertices. Choose Filters->Sampling->Poission-disk sampling. I have no idea what Poission-disk sampling is, but a value of 250 seems to work for this tutorial. Depending on how many verts you created in Step 3, you’ll adjust this number up and down.

I think this just picks a subset of the group of vertices you just created with the Loop subdivision. Remember: you’re in the cargo cult now. Doesn’t matter why this works.

If you click on the POINTS view icon, you’ll see your points. You can click on the SMOOTH view icon to make the model look solid again.

Step 5: Apply Voronoi Vertex Coloring. This is where the magic happens. Select Filters->Sampling->Voronoi Vertex Coloring and make sure the Back Distance checkbox is checked.

After you click Apply, you should have something Voronoi-ish. We haven’t actually made the holes in the mesh that give shapes their cool Voronoi webbing. All we’ve done is color the sampled vertices.

Step 6: This is the step that took me forever to figure out. I’m sharing my process with you because I hope it will help alleviate my MeshLab post-traumatic stress disorder.

Before you do anything else, you must collapse the mesh layer stack. While you’ve been following these instructions, MeshLab has been quietly building a construction history for your sphere in the background.

If you don’t merge the mesh layers, you’ll be stuck at this step forever.

Click on the LAYERS icon.

This will bring up the Layers sidebar. Right-click on the Poisson-disk Samples layer and choose “Flatten Visible Layers” from the contextual menu. Make sure you click “Apply” in the windoid that pops up.

Step 7: Now you just need to remove the interior faces from the sphere. This is easy. Go to Filters->Selection->Select Faces by Vertex Quality.

What is vertex quality? I don’t care. Cargo cult.

Check the Preview checkbox and fiddle with the sliders until the selection looks the way you want it to. Click apply and then close the selection windoid.

Click the Delete Faces button. It’s on the upper right, just above the layers sidebar. You’ll get a single-sided Voronoi webbed mesh.

Step 8: Refine the mesh. This mesh is a little chunky, but Meshlab has a number of smoothing algorithms. Select Filters->Smoothing, Fairing, and Deformation->Laplacian Smooth, click the Preview checkbox, and smooth the mesh as many times as you like. Click apply and close the windoid.

Step 9: Extrude the mesh. Your sphere is still a one-sided surface with no volume. In theory you can fix that by going to Filters->Remeshing, Simplification, and Reconstruction->Uniform Surface Resampling (Who writes these menu items?) and fiddling with the values until you get a surface with a thickness you like.

Or you can do what I did, and export the single-sided mesh and bring it into Maya, or 3DSMax, or whatever the kids are using these days to extrude their geometry.

Slightly more advanced Voronoi cargo cult behavior

We’ve Voronized a sphere, which is like the “Hello, world” of Voronizing.

BUT. Unless you’ve got a stereolithography printer like the Form1, you’ll be hard pressed to print your sphere on your Replicator or your RepRap without support.

(See this Twitter conversation in which I attempt to dupe Formlabs into printing my Voronoi bloxen, but they don’t, because they are too clever. Or perhaps because they are CHICKEN. bock bock bock @bvicarious is collateral damage in this exchange.)

Besides, you didn’t come here to learn how to Voronize spheres. You want to Voronize something you made or downloaded elsewhere. Something with some detail.

Let’s say you want to apply this process to a model with edges, like a cube. You’ll find yourself stymied after step 3 when the Loop Subdivision turns your cube into a rounded globule.

You’ll need more detail at the edges of your model. I have no idea how to do this in MeshLab, but I can make a cube in Maya pretty fast. Here’s a cube with beveled edges. Download it here if you want to try this yourself.

Import the cube into Meshlab and Loop Subdivide it a few times and you’ll see that the edges stay fairly defined. Go through steps 3-7 as before and you’ll wind up with this:

Welcome to the Voronoi Cargo Cult! We have guavas and beer every Wednesday after work.