World Maker Faire: 3D printed tower defense

September 23, 2013

Moving Day!

April 12, 2013

I’m moving this blog over to a self-hosted site.

I’ll be posting new content at Please update your bookmarks and links accordingly.


Dualstrusion with MakerWare Beta 2.0

March 19, 2013
TL;DR summary: The UI’s handy and the MakerBot slicer is mind-blowingly fast, but I had a great deal of difficulty getting a dualstrustion to print with MakerWare.

I opened a support ticket with MakerBot yesterday, trying to get MakerWare to connect to my bot over USB. If you’ve read yesterday’s post you’ve seen the litany of troubleshooting steps I’ve already tried. Today I’m thinking maybe I’m due for a firmware upgrade, but we’ll see what MBI has to say before I fix things that are only slightly broken.

While I’m waiting for that request to percolate through the support structure I thought I’d try a workaround: printing from the SD card. I’m interested to see how MakerWare’s new dualstrustion generation works, because ReplicatorG’s method is a little kludgey.

This is MakerWare running on OSX 10.6.8.

I’m going to print my Magic: The Gathering Vampire and Cat tokens, because I already have black and white ABS filaments loaded. One color for each token.

I import the cat and MakerWare helpfully asks me if i’d like to put the model on the build platform. Yes, yes, I would like to do that.


I can command-c/command-v to copy and paste multiple cats onto the platform, and Makerware automatically places them next to each other. This is quite a nice little feature.

Just for fun I see if MakerWare will let duplicate cats off into empty space. It does.

lots of cats

The delete key rapidly relieves me of my extra cats. Next I import the vampire. The vampire and cat are cohabitating, which needs to be fixed before I can print. That’s a simple click and drag.


I’d like to have a keyboard shortcut for “Add,” if anyone from the dev team is reading this.

MTG Vampires are either black or red, so I need to change the vampire’s color. I click the vampire token and then the Object button, which brings up the properties of this instance.

There’s a strange, unused text field under the dropdown menu. No idea what this is for. I can’t click or type in it.

text field

Ah. It turns out this alleged text field is a white color swatch indicating the color of the model. I find this out when I go to change the cat’s color. A label would be helpful here for first-time naïfs like myself.

It’d be nice to have a double-click on the color swatch bring up a color picker. As is I have to go to the Settings button on the other side of the screen.

I go to change the color of the extruders in Settings, and MakerWare crashes.

changing colors

So. I retrace my steps and I’m back in business in two minutes.

Exporting the .thing to a file is a single click of the Make button, and I don’t have to mess with any settings here. I just choose “High Quality.”


Out of curiosity I poke into the Advanced settings. The speed while extruding /traveling seems really fast to me– I’m usually printing around 45/65 and MakerWare defaults to 80/150.

But I’ll give it a go since I’m trying to approach this software as if I’m a n00b who just unboxed my machine.

Skeinforge is the default slicer for High quality. The slice starts OK, and then seems to hang around 66%. I’ll give it a few more minutes and then try again.

I come back three minutes later and the slice weirdly jumps back to 33%. Two minutes later it does some “Weave” business, then a print-to-file step, and finally it’s done! Total slice time, about 15 minutes.

Remember I can’t print via USB yet, I’m exporting a .s3g file and then printing from the Replicator’s SD card slot.

The first layer looks like this:


It looks like some piece of software, either MakerWare or Skeinforge, forgot to take the cat offset into account when building the gCode for this print.

So I try it again with the MakerBot slicer, which slices so quickly at first I think something’s wrong. It takes literally less than 30 seconds.

I believe that somewhere between 1.0 and 2.0 the in-application name of this slicer got changed from Miracle Grue to MakerBot Slicer. This is disappointing.

This print, too, failed in exactly the same fashion, so it’s not Skeinforge that’s the problem. I’m looking askance at you, MakerWare.

So I move the cat over a little bit, to force the geometry to change in the reslice.


Also, as long as I’m here I’m going to drop the travel speeds to something I’m more comfortable with; the machine’s rattling violently at the default speeds. Here’s the result, still overlapping.


I’ll try one last time with plenty of distance between the models printing at 45/65 travel rates.


And finally I get something close to a decent print.


The vampire printed fine, but there are little bits of black filament embedded in the white plastic– I have no idea how they got there. They don’t look like they rubbed off the left extruder head, and they don’t show up when I print models with a single extruder.

My hunch is that this is an atypical dualstrusion print– maybe I had such a hard time because MakerWare thinks all dualstrusion prints are intended to be fused together and not two models separated by a lot of space. I can’t say for sure.

It’s disappointing. MakerWare’s got a lot of promise but it’s not going to be a regular part of my workflow for a while.

Everybody was kung-fu fighting.

February 14, 2013

I accidentally created a kung-fu rat thing while working on a new model this morning.


The Many Faces of Comedy

November 27, 2012

I had a lot of trouble deciding which photo of Zhengspawn Alpha to use for Ye Olde Arrow Through the Head Gag, so I’m putting them all here.



Elated Kristen Stewart?

This model uses two halves of a #2 pencil as the arrow shaft. Comedy. Gold. download

Complexity is free.

July 11, 2012

The spools of ABS that I purchased when I bought my Replicator are finally about to run out, so I went online to get some new ones.

I ended up getting some green ABS and blue PLA from Amazon reseller jet_jet2004, who was nice enough to throw in an extra kg of PLA as a courtesy. Thanks, Jet!

I got the box open and discovered that the spools don’t fit on the back of the Makerbot. The spool bores are way too small. Opportunity!

I opened up the Tinkeriffic Gear Set, did a little vertex slice and dice, and printed a pair of spindles that fit snugly in the holes. Five minutes of Tinkertoying later and I have a functional spool setup for 40mm plastic spools.

Last week I was listening to Science Friday: Can 3D Printers Reshape the World? when Ira Flatow was interviewing Bre Pettis, Hod Lipson, and Terry Wohlers.

Wohlers said something that stuck with me: “With these printers, complexity is free.”

Complexity of design is no longer a barrier to (small scale) manufacturing. The complexity of a design is baked into the process; there’s not much difference from the human perspective between manufacturing baroque and mundane objects.

Press a button, get an object. Let the robot do the work.

There’s no reason for the wavy spokes on the spindle except to adhere to the Rule of Cool. But they exist, and it doesn’t take any more human effort to have them than it would have taken to omit them.

There are many. other. fine. spindles. on Thingiverse, but think this one is the first that’s designed with Tinkertoy compatibility in mind.

Download it from Thingiverse.

…Zheng3 is on Twitter now.

May 18, 2012