Category Archives: Uncategorized

Printing with NinjaFlex on a Type A Machines 2014 Series1

TLDR: print slow and hot with NinjaFlex. It ain’t rocket science, but does require a little attention to details if you’re used to PLA or ABS. If you’re using Cura you can download my Type A Machines 2014 Series 1 profile here.

Our most recent Kickstarter was a smashing success! We were 119% funded with 140 backers. Watch this space for a comparison/post-mortem describing the differences in funding among the several Kickstarters we’ve launched, successful and not so much. I learned a great deal with Strongholds and I’m eager to apply the new knowledge and analytics to the next crowdfunding effort.

Here at Zheng Labs we’re ramping up to start the print-a-thon for backer reward fulfillment, but we have a little side project to get out of the way first. Scoundrels that we are, we’re using the slow trickle of backer survey returns as an excuse to not engage with the following print ticket:

print ticket

That’s-a-lotta-printing, my friends. We’ll get started this evening, I promise.

The Easter Bunny was kind enough to drop off a roll of NinjaFlex last week, so before the printer gets ocupado producing Citadels and Eyries for the forseeable future we thought we’d give flexible filament a try.

Loading NinjaFlex into an extruder can be like shooting pool with a rope. I found that my venerable Replicator1 sucked the NinjaFlex right in without issues, but the faster G2 extruder on the Series 1 caused the NinjaFlex to bind up, thusly:


The trick is not to use OctoPrint’s Extrude button to pull the filament into the extruder– it pulls the filament in too fast, the filament backs up inside the nozzle and then starts folding upon itself and turning into silly string.

Instead, just heat up to 240°, push the lever on the side of the extruder, and manually push the filament in until you feel it hit the bottom of the nozzle. Make sure you’ve got good thermal conductivity between your hot end and nozzle too; a liberal application of thermal paste will be quite helpful.

Thermal paste fixes so many 3D printing problems.

Print settings: I’m at 240°, printing at 20mm/sec with .2 layer height. Retraction at 50mm/sec with a distance of 2mm.

Rex turned out nicely, printed on glass with Elmers’ glue stick. Then I mushed him under some PT weights.

rex crushed

(You can of course download Rex from The Forge.)

In other gnus: there will be a lot of human downtime while I’m printing all those Citadels and Eyries, so I’ve started modeling work on the Next Thing. Here’s a peek.


#staytuned. This project’s going to be buckets o’ fun.

Seej 2015: The People Have Spoken

People's Choice Award

Hey, so this is pretty great! Thanks to hundreds of votes from dedicated fans, The Seej 2015 Starter Set just won Pinshape’s People’s Choice Award!

I’m truly honored and thankful that y’all took the time to vote for Seej. As promised, I’ll be designing and modeling a 3D-printable tiara to commemorate the win. #staytuned, my friends.

Apparently Robber Rex finished second in the “Best Simple Model” category and he is pissed.

There Once Was a Project ’bout Venus


Longtime readers of this blog– both of them– know that here at Zheng Labs we’ve got a couple of rugrats running around the place. The older one’s in high school now, and has a practiced eye roll that earns perfect 10’s even from the Romanian judges. She’s not the subject of this post, although you can see photos of her pupal stage here and here, and some free 3D printable models to boot.

No, my friends, this week we bring to you the chronicle of my younger spawn and his adventures at the elementary school science fair. Each year his school puts on an open house for prospective families where they might explore for themselves the Hogwarts-like environment at one of Wisconsin’s fine public charter schools.

This open house features a gymnasium full of the kids’ long-term science projects, and is always a treat for those inclined to make things that go kablooie with papier maché, baking soda, and a little CH3COOH.

In years past procrastination and lack of interest have led my son to flail helplessly in front of a sloppy trifold when the time to present his project came, and this year we were determined not to repeat that particular learning experience. We got started early, enlisted a 3D printer, and won the science fair.*

*on “winning:” the event is actually noncompetitive and the school doesn’t give out prizes. I’ll define winning as spending a couple hours in the basement with my son, teaching him how motors and voltage and switches and soldering irons and burn creams work. Plus the look of unadulterated joy on Xiao Zheng’s face when the project worked: priceless. Scroll down to the bottom of the post for the big payoff video.

Also, the kid who actually won the science fair was the one with the trifold cheerfully labeled “Exploring Uranus.” That kid’s going places and has either fantastic or clueless parents.

Astute readers may have surmised that this year’s theme was space science, and the thrumming gymnasium was packed, absolutely packed with elementary school children wearing astronomy-related costumes. One kid was a dead ringer for Carl Sagan (red turtleneck included). Galileo and Halley’s comet were easily identifable from across the room. One young man made a fantastic Pathfinder rover hand puppet, a young lady was fetchingly dressed as the day and night cycle complete with helium balloons tied to her pigtails, and much aluminium foil was spent in the pursuit of knowledge.

Soviet science was well represented, too. The neighbor kid dressed up as Sputnik, and there was even a kid in full bright-orange Yuri Gagarin drag. Imaging getting that costume past the a 1950’s school board here in Appleton, Wisconsin, hometown of national disgrace and Ted Cruz lookandthinkandsoundalike Senator Joe McCarthy.

McCarthy’s grave is right down the street, should you feel the need to urinate.

I’d post photos of the science fair, but! Kids’ privacy issues. You know the drill. Local parents: if you’d like to share a photo of your kid’s costume, send it my way.

好久以前, back when Zheng himself was xiao, Dad and I spent many evenings in our basement laboring on school projects. In all fairness it’s safer to say that Dad did the heavy lifting and I just provided parameters, but man those projects were the envy of the other kids in elementary and middle school. I wish I had photos of the tornado diorama, or the sculpture of Zeus made of toilet paper, shellac, and Ivory soap flakes (!) or that Roman aqueduct we (Dad) made out of grout and PVC. Or the paper bag mountains with joint compound glaciers. Or the passive solar house model made out of foamboard reclaimed from the dumpster at work.

Thanks Dad, for doing those projects with me. I’m doing my best to pass your creativity down to your grandkids. Cir-cle of liiiiiiiiiiiiiiiife!

But I digress. This is a 3D printing blog first and foremost, and you’re here to read about the process of creation.

We got the trifold part of the project out of the way first, and settled into working on the costume part of the presentation. Our challenge: making a wearable model of Venus. Xiao Zheng’s first idea was to hand-letter the word “VENUS” on a piece of cardboard and hang it around his neck. He’s literal that way sometimes.

A planet-like sandwich board was also considered and quickly discarded as “stupid” and uncomfortable to boot. We gnashed teeth and rended garments for a while before remembering that his bike helmet has a GoPro mount on it, and would be a perfect platform on which to place a model.

The model of Venus itself is nothing fancy, just a lightweight ball of bubble wrap shrouded in painted tissue paper. It masses approximately 116 grams. The actual planet Venus masses 4.867 × 1027 grams.


I introduced my son to the joy of inadvertently huffing spray paint fumes in the garage, which he liked. Maybe too much.


Just attaching Venus to a helmet’s really not enough when the other kids are dressed up as Saturn V rockets, so we had to take it to the next level by making the model spin. I’ve got a bunch of old DC motors kicking around because of course I do, but we quickly realized that even if we could attach the motor’s axle directly to the model, it’d spin way too quickly.

We needed to slow the spin and the solution, as it is to so many things, is gears. Fortunately, I’ve already got some at the ready.

So a few minutes’ modification in Maya and we’re off and printing. Pro tip: gaffer tape works astonishingly well as a print surface for ColorFabb’s PLA/PHA. Note that there’s a cup integrated into the top of this gear to give the planet more surface area for adhesives.


Next we’ve got to get the gears onto the helmet, and fortunately there’s a GoPro-compatible mounting system in the Forge. A few more minutes of vertex wrangling and a couple of test prints and the mounting system looks like so:


(You can download the models here if you’d like to take a peek at them.)

The rotation is controlled with a momentary switch hidden in the kid’s pocket. Hold the button down and Venus spins faster and faster. Of course, my kid’s teachers aren’t pants-wetting bigots and he’s white as Wisconsin snow and not named Ahmed, so nobody batted an eyelash at this suicide-bomber-looking pushbutton setup. It’s even RED.


Fun fact: Venus’ day is 243 earth days long. I learned this from the aforementioned girl dressed as the day-night cycle.

Everything’s gaffer-taped together to insulate the solder joints and the wires are hidden under clothing.

The project survived the entire night on one set of 4 AA batteries and finally met its demise when my son, in an all-too-typical display of spazzy exuberance, head-butted the kid dressed up as a Soyuz capsule during cleanup and Venus went spinning across the gym floor and into the hallway.

Lao Zheng out. Thanks again, Dad, for teaching me how to do a science fair project right.

D is for Direwolf!

Here’s some very cool technology from Sketchfab that lets users embed 3D content just about anywhere. Blogs, Facebook, Kickstarters, you name it.

This is one of the proof-of-concept models I developed for Dungeon Blocks. Go ahead, give it a spin!

Folks unfamiliar with 3D printing might wonder why the indentations for the block’s mortar are angled. This is a common 3d printing modeling technique to ensure successive layers of hot plastic have something beneath them for support. If those mortar lines were 90° angles, the bottom edges of the stone blocks would probably droop downwards on most FDM printers.

Another design note: the bottom of the block is completely flat to help it adhere to the printer’s build platform.

Have I mentioned that there’s still time to back the project? We’re at 42% and could use a few more minds to help decide which fantasy tropes are featured on the final set of blocks. Check out the Kickstarter here.

A Leaf On the Win

TL;DR: Love this car. Not going back to internal combustion engines if I can help it. Ever ever ever.

The imminient Kickstarter has things all a-bustle up in here; we’ve built the Pyramids, the ruh-ruh-ruh of frenzied sawing and Italian curse words pour from the windows of Leonardo’s Workshop (marone-a-mi!), we’ve converted eight of ten citiziens into scientists, and I’ll be thrice-damned if the Zhengians aren’t going to beat the Mongols to Alpha Centauri.

The hard work’s done, and now it’s just a matter of getting the publicity photos, writeups, and video in the can. As we like to say in this bidness, the last five percent takes as long as the first 95, and as a fan of doing things fully-assed I’m working hard to apply the jeweller’s rouge to this project everywhere I can. I think you’ll be amused by what we at Zheng Labs have accomplished over the last few weeks. Here’s another teaser image:

But! Elsewhere in our multithreaded civ the fires of Isengard still burn, and we can’t help but crank out a new bauble every now and then.

The lovely and talented Mrs. Zheng3, who, in addition to being lovely and talented, is also geeky and eco-conscious and did I mention lovely and talented? recently traded in her gas-guzzler (which if we’re to be completely fair was a gas-sipper but had the unfortunate habit of failing to start in the cold weather so common here, in the windswept reaches of the U.S. north, where red-blooded patriots cast steely, suspicious glares towards our Canadian neighbors yet still enjoy their comedians, country singers, Shatners, and tar sands, but I repeat myself) for a shiny new all-electric 2013 Nissan Leaf, which so far this year has performed admirably, if somewhat disquietingly in its quietude to those accustomed to the rumble, shimmy, shake, and hydrocarbon stank of internal combustion engines.

With this Leaf we’ve no need to visit a gas station ever again except to slake our thirst for jerkies, but we are required to charge the vehicle occasionally. The boomslang of a cable included with the car has been flopping around on the north side of our garage for the last couple of weeks.

We don’t countenance cable clutter in this house, young lady, so I put forth this wall-mounted clip specifically designed for the Leaf.

clip 1

You can download this model file along with many, many others for free from The Forge. I recommend printing at high infill for this model. Glue the clip into the base before affixing to the wall.

Eveything’s Better With Drywall Screws, so drill two pilot holes an inch apart and hang the base from a stud. (2.5 cm in the STL, actually, but I live in the USA, where outdated systems of measurement are a bizarre source of quasi-xenophobic national pride, so inches it is.)

You’ll need several leaves to support the weight of the cable. I’ve included leaves in different orientations so that you can create a nice pattern on your wall if you so choose.

Now, about this car. is primarily a 3D printing blog, with occasional forays into technology and gadget reviews. This new Leaf is the most expensive gadget I’ve ever owned, (although adjusted for inflation my circa 1998 Softimage workstation might have given it a run for its money if the Leaf’s handicapped by the generous federal electric vehicle tax break) so I think it deserves a mention here.

Heads up: I’m not a car guy and never have been. Driving’s always been a necessary evil, and I’ve always been more interested in DPI and megahertz than torque and horsepower. I respect, but have never fully grokked, people who change their own motor oil or drive for any reason other than to get from A to B.

The lovely and talented Mrs. Zheng3 was driving a 2011 Mini Cooper before its wintertime air intake troubles became frustrating enough to consider a trade-in. We test drove two other cars before settling on the Leaf. The Camry hybrid felt like a rental and the 2014 Prius handled like a brick with faulty shocks.

The Prius UX, what with its sweeping gearshift arch and gratuitous, minimally informative graphic design, felt like the designers ripped off the bridge of the TNG Enterprise. This would have RULED! in 1993 but today felt like a hamfisted marketing ploy targeting GenX geeks. Major, major, turnoff, Okudas be praised.

Remember that we’re comparing the Leaf to a Mini Cooper, the gold standard for small-car handling in my limited experience. The Leaf comes out OK in this matchup; it’s not a sports car, but it’s peppy enough, corners well on city streets as long as you’re not trying to be Vin Diesel, and accelerates just fine getting onto the highway. I thought I’d be driving a golf cart and was pleasantly surprised to find that that this all electric vehicle is, in fact, an ACTUAL CAR with a comfortable ride.

Here at Casa de Zheng every car gets a name. We sent Mini Cooper Shadowfax to the glue factory and replaced him with Radagast the Leaf. Driving the smallish Leaf through the city does resemble being on a sled pulled by giant rabbits dodging wargs. By which I mean oblivious soccer moms, crunked-up on Chobani and coconut water, careening around in Escalades.

Radagast emits a whisper-hiss-whine while it’s in motion. No chugga-chugga here. For that matter, no changing motor oil, ever. It doesn’t exist in this vehicle. The car’s eerily quiet, and at idle there’s little aural difference between an active and passive Leaf. Only the radio and heater fan let you know the car’s been turned on.

The car beeps when it’s in reverse, which is a nice touch for pedestrians in parking lots who are unaccustomed to mostly silent cars.

The Leaf’s ECO indicator helps the driver maximize range by gamifying the feedback display; drive efficiently (no jackrabbit starts, judicious use of regenerative braking, and the like) and the Leaf will sprout a little conifer in your dashboard. Continue to be nice and you’ll build up a grove of tiny tannebaums. Careful motoring during the short jaunt to pick up Elder Zhengspawn from school will net you at least a couple of branches, and of course there’s spousal competition to see who can build a tree the fastest.


Keyless entry, bluetooth sync, heated front/back seats, and a reverse-angle camera come standard with the Leaf. These are all nice features lacking in my 10-year-old Outback.

The heated steering wheel. Wow. Suck it, polar vortex.

Lest you think it’s all sunshine, roses, and redistributed CO2 emissions over here, gentle reader, I must mention two minor complaints about the car’s user experience.

First: the gearshift knob is a tiny little nub of a thing that I can only grasp with my fingertips. The designers must have had a reason for giving it such a low profile, but I can’t fathom what that reason might be. I’d ask Nissan to either put the gearshift on the steering column or make it taller so it can be grasped with the palm.


Second, and this is the bigger annoyance, is that the button that opens the charging port door does not self-illuminate. You’d think this would be a minor problem, but oop North it gets dark in wintertime, yo. Twenty years of driving internal combustion engine cars has conditioned me to just walk away when I’m done, and by the time I remember that I’m supposed to charge the car I’m reduced to using my phone as a flashlight, fumbling for the button.

I’ll be using this as an opportunity for personal growth, reconditioning myself to open the charge door whenever I get into the garage.

On charging: the lovely and talented Mrs. Zheng3 has a five-mile commute, so at the end of the day she’s still got another 40 miles of range left before a recharge, but we plug it in every night anyway. The aforementioned boomslang runs off household 110V AC, so no fancy rewiring of the garage is necessary. Just plug in at the end of the day and wait. Nissan engineers take note: it’d be nice if the cable had an LED at the business end so I could use it as a flashlight when I’m stumbling around a dimly-lit garage in February.

RTFMing will reveal one bit of WTFfery: The Leaf’s trunk is touted as being able to hold two golf bags, and provides far-too-detailed instructions on how to get two golf bags, specifically two golf bags, into your car. They spend an entire paragraph on this, and some overworked graphic designer had this diagram on an Adobe Illustrator todo list at one point.

golf bags

Note where the designer’s eff-it-o-meter lurched into the red zone on the lateral view and he depicted the golf bag cross-sections as sharp-cornered rectangles.

Even by the standards of eccentric units of measurement golf bags seems peculiar, especially for a car with such nerdy appeal. Nissan. Give me a meaningful volume for trunk space. MegaD20’s. Picoparsecs cubed. Golf bags? Honestly. How much LARPing gear can I fit in this thing? That’s information I can use.

Tooling around our small city, we’ve never even come close to the car’s limit in our weekday and weekend routines, so range anxiety hasn’t been an issue yet. We’ve still got the ICE Outback if we need to go for a long haul somewhere, but I highly, highly recommend the Leaf for anyone with predictable and relatively short daily driving patterns.

Having exhausted all the intuitive and expected options of a new car, we’re gradually discovering Radagast’s not-so-obvious bells and whistles. The curious will find that the above-linked manual reveals the secrets of Radagast’s built-in 110V outlet, Wi-Fi integration, luggage hook, and other minor niceties.

I find myself making excuses to drive the Leaf when the lovely and talented Mrs. Zheng3’s not using it. I’ll even volunteer for errands I’m not particularly interested in doing, just to drive the car.

Which I guess is what people who drive for reasons other than to get from A to B feel like. Huh.

Lightsmithing at Maker Faire

Here’s the third in my series of Maker Faire Gems posts where I’ll be discussing interesting stuff I found at Maker Faire NYC a few weeks ago.


One of my personal highlights was meeting the crew from Providence creative community AS220.

Andrew Lloyd Goodman’s LightSmithing project was fascinating. He helped me make the above image on Sunday morning.

Here’s how it works: Andrew hands you a big honking Mjolnir-like hammer.

The hammer’s got a bunch of LED’s on its striking surface and a (mercury switch? accelerometer?) somewhere in its head.

Andrew guides you into a darkened booth.

Hiding beneath a plexiglas table is a camera set for long exposure, lens pointed skyward through the transparent surface. Someone has strewn flowers on the plexi.

A herculean swing of the hammer creates a brilliant flash of light, and a gentle shake emits just a glimmer. The camera records the results of every swing and creates an image like the one above.

Timed Screen Capture on OSX

I’ve done a couple of 3d printing timelapses using a little application called Iris for OSX. Iris doesn’t seem to like to save my movies for some reason, but it at least gets the output from my fin de siècle webcam onto my laptop’s display so I can do something with it, like capture the screen once a minute and write it to a file using a Python script.

The Scrying Pool to the right uses a very similar process to take snapshots of the Forge while I’m working.

I’ve written this script to be as simple as possible for a novice who knows very little about programming. Being familiar with the concepts of variables and loops before using this will help, but really you should be able to paint-by-the-numbers and get one screengrab a minute without any extra work.

Bonus: some version of Python comes pre-installed on OSX, so you don’t have to install anything to get this to run.

To use:

  1. Make a new folder on your Desktop named capture
  2. Open TextEdit.
  3. Copy this script into a new text file. Save it on your Desktop with the name
  4. Open the Terminal.
  5. In the Terminal type python ~/Desktop/

That’s it! You can stop the script from running by hitting Control-Z in the Terminal.

# everything following a hash sign is a comment. Python doesn't execute comments. They only exist to make your code more readable.
# this script requires that you have a folder on your desktop called "capture"

import os,time

delay=60 # this number is measured in seconds.
i=0 # i is a common variable used for loops. We'll use this in the infinite loop later.

while i<1:

# this is an infinite loop! we never change the variable i, so i is always less than 1.
# this script will run forever. You have to quit it with CTRL-Z.
# see how everything inside this while loop is indented by one tab?

# create a command that the Terminal will execute. screencapture is built into OSX.
# str(counter) turns the integer "counter" into a string so that it can be added to the command string.
# if you don't do this, Python will throw an error.
# the -x option turns off the screenshot noise.
# the -o option tells the OS where to save the captured image.
# ~/Desktop is the command line shortcut to your Desktop.
# this script will name the files capture.1.png, capture.2.png and overwrite those filenames in ~/Desktop/capture/

cmd='screencapture -x -o ~/Desktop/capture/capture.'+str(counter)+'.png'

# have the OS execute the command.

# let the user know what you're doing by writing the command to the Terminal.
print cmd

# increase the file number by one.

#wait a little bit. You've already defined delay up at the top of the script.

# this comment is outside of the while loop.
# if our code were to continue, it would start here.
My apologies for the meshuggeneh formatting on the Python code above. Can’t make it work without a CSS overhaul for the entire blog.

Dualstrusion with MakerWare Beta 2.0

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.