Monthly Archives: September 2013

Anatomy of A Remix



One of the highlights from World Maker Faire 2013 in NYC was meeting Thingiverse All-Star cerebus333. He’s friendly, engaging, and incredibly prolific; I can’t recall a week’s recent passing where he hasn’t posted at least one new model to his collection.

I was honored to take home an autographed Rock Frog from Cerebus’ collection, and I promised him that I’d take a shot at remixing his work when I got back home. Here’s the original model, standing about 7 inches tall.


Cerebus has designed the Rock Frog to print reliably on an FDM printer, and print reliably it does: the mesh is manifold and it’s physically quite stable on the build platform. My plan is to re-pose the original and turn it into something usable as an RPG elemental or golem miniature, and that’s going to require some geometry edits.

Step 1

Cerebus designed the Rock Frog’s knuckles to lay flat on the printing bed. If they’re going to potentially be raised up in the air they’ll need to look more like fingers. I’ll delete the old flat surface and replace it with some vaguely-knucklelike ridges. A little sculpting here and there and we’ve got something that looks good enough for now– my experience with 3D printing tells me that much more detail here isn’t going to print at this scale so there’s not much point in overworking the model.

Note the strange triangulation in the sole of the foot, because I’ll fix that in step 2.

I’ve split him in half down the YZ axis so I only have to fix one hand before mirroring and rejoining the model.

edited fist

Step 2

The foot geometry is fine for printing, but not so good for deformations. This should be a straightforward fix, and afterwards Rock Frog will be able to put some weight on the ball of his foot.

fixed feet

Step 3

Rock Frog’s mouth is closed in the original. I’ll find the inside crease of his mouth, split the geometry, and then open up his mouth. A note for folks not used to working with character models; it’s generally easiest to work on one half of a model and then mirror it, which is why the original Rock Frog has been split down the middle here.


Step 4

Bipedal 3d characters are usually modeled in T-Pose, with arms outstretched. This pose helps when assigning weights to vertices, step one in rigging a character. I’m not going to invest a lot of time in a full animation rig here, just enough to intuitively bend Rock Frog at his joints.

Rock Frog’s legs are already in a good position for vertex assignment, so no adjustments need be done there. Once I’ve got him in T-pose I’ll inspect the mesh one more time to make sure the mesh is closed and manifold.


If you’d like to pose Rock Frog on your own, go ahead and download the t-posed model.

Step 5

I reach way back into the mists of time for inspiration, back to a time when Xiao Zheng was a fifth grader surreptitiously poring over the 1st Edition AD&D monster Manual under the covers. I move some joints around here and there until Rock Frog more or less resembles David C. Sutherland III’s classic drawing of an earth elemental, with allowances made for the gravity-plagued medium of supportless FDM printing.

The posing created some self-intersecting geometry where I didn’t bother to weight the vertices properly. Bad mojo. I can easily fix this by painting the vertices with a smoothing algorithm, but doing so while the model’s rigged to joints can be slow and produce unpredicatble results.

At this point it makes sense for me to detach the geometry from its joints, freezing Rock Frog in this position. I’ll save a version of the rigged model in case I want to re-pose him later.


And now a test print. Almost everything prints OK, but the heel of his right fist hangs out in space just a bit too much. Frankly I should have seen this coming. Part of the problem is that I’m printing at a .3mm layer height for the test, but there’s just too much overhang there even with a higher-resolution print.


The model’s now detached from its joint system, so if I’m to edit that fist I have to do it without the benefit of a weighted joint system. This is a small tweak, so I just throw a lattice around the fist and forearm instead of backing up to the beginning of step 5.

lattice fix

The fist on the second print looks much better, so I’ll go back and add some aesthetic tweaks. I’d like to roughen up the surface with some stony protrusions. Much of this can be done with Maya’s poly sculpting tools, but I add some nicely geometric gems for contrast too.


The gems stuck in the Rock Frog’s back are easy to model but they don’t retain their sharp geometry in the final print. I’d like to see how this prints at a higher resolution.


This model and others like it are of course available for free download in The Forge. This post is the first in my series of Maker Faire Gems, wherein I’ll be blogging interesting stuff I discovered this year that might have slipped through the bigger outlets’ coverage. #staytuned

Radiant Li Beta: First Impressions

TL;DR summary: Experienced Minecrafters will have no trouble navigating the interface, but Li needs more documentation or a tutorial mode for inexperienced users. This beta is well on its way to dual-purposing the Minecraft learning curve as a way to create 3d models. No STL export capability as of 9/10/13, so for now it’s a curiosity while we await the release of the Lionhead 3d scanner/printer. This could be big.

There’s phrase from Dao De Jing : 千里之行,始于足下, or, “A journey of 1000 li begins with a single step.” (A li is a Chinese distance measurement that’s roughly 1/3 of a mile.)

One must undertake the grandest journeys on one’s own initiative, and that’s what Radiant Fabrication plans to do with its much-anticipated Lionhead All-in-one scanner and printer.

Li is the name of the Lionhead’s scanning, modeling, and printing software. Li uses a Minecraft-like interface to build 3d models locally, without the internet connection required by services like Printcraft. In theory it’ll run the Lionhead 3d printer/scanner, but I haven’t tested that capability yet.

Li gets its name not from Laozi, but rather from the rabbits of Watership Down. In the world of talking rabbits, li translates to “head.” In our universe, the one sadly lacking anthropomorphic hares, Li is the one tool, the head, if you will, that you’ll need to run the Lionhead when it ships: scanning, editing, and printing will all controlled from Li.

Big old caveat: Li is a Beta, and it had been released for less than 24 hours when I got to it. Expecting a completely polished user experience would be unfair.

So! I launch the software and start my stopwatch. The goal is to mark my metric for 3D software accessibility: Time To Cube. How long does it take to design and export a 1x1x1 cube in a format that I can use with one of my 3d printers?


And, go! The UI looks a lot like Minecraft, or at least what I remember Minecraft to be circa mid-2012.

Blink and you’ll miss a small notice that says “Press F1 for Help” on startup. This notice really needs to be made more clear on first launch– I only noticed it after quitting and restarting a couple of times once I’d backed myself into a corner. This notice seems to go away on its own if you leave the application alone for a few seconds.

Li doesn’t ship with a README and documentation as of today appears nonexistent, so I’m on my own for figuring out how things work. I’m not a Minecraft guy, so I go with what seems intuitive and press the 2 key to give myself a cube and plunk it down. I click on the ground and get bupkis. No cube.

AH! Left-click to Remove, Right-click to place. This seems really non-intuitive to me but I’m reminded this is the way it’s done in Minecraft. When in Rome and all that.

It turns out the tools at the bottom of the UI are best thought of as volumetric brushes. Right-click to place a sphere comprising a bunch of Minecraft blocks, left-click to carve a sphere’s worth of blocks from an existing structure. Now it makes sense. It looks possible to make custom volumetric brushes, too, which conjures fevered dreams of painting with ZOMG VOLUMETRIC SQUIRRELS

The software defaults to a single voxel placement/deletion mode, which will be handy for making simple models or trimming a little bit here and there from a model built from bigger primitives.

Heads up: with a few exceptions for illness, vacations, zhengspawning, and funerals, I’ve been using Maya for modeling almost every day for the last 15 years. I’ve got Maya reflexes, Maya muscle memory, and Maya expectations. My existing 3D experience is going to taint any interaction with new software. I also haven’t played Minecraft in over a year, so while I’m familiar with the basics my WASD+mouse navigation skills are mushy.

So I floundered around in Li’s UI for 26 minutes (!) before turning off my stopwatch and handing Li over to Elder zhengspawn, who is twelve years old and recently stopped playing Minecraft in favor of WoW.

She made a 3x3x3 cube in less than 25 seconds. Then she made a 正, and was well on her way to sculpting that rocket motor Elon Musk’s been Tony Starking with lately before I kicked her off the laptop to try again.

Having observed the master at work, I threw myself back into the Time To Cube test. Twenty seconds this time, now that I know what I’m doing.


I’ll just export this model as an STL so I can take a look at it in netfabb and evaluate the mesh, and…

unforeseen problem…phooey. There’s no way to export one’s model from the current version of Li. This is a little disappointing, because I was hoping to evaluate the mesh and maybe give it a test print on my Replicator.

One can save an model as a .radiant file, but as far as I can tell doing so creates a closed binary. I’ve tried to open the .radiant cube with Textedit, Netfabb, Meshlab, and even cat and got nowhere. Opening up the .radiant format to experimentation from the outside could foster all kinds of creativity, so I’ll put that on my feature request list along with STL export.

A .radiant file containing a 3x3x3 block cube is 27MB. Lawdy, what’s going on in there?

I’m going to wait for the next version of Li before I try again, so #staytuned. This software’s got a lot of promise as a tool for younger modelers, but without an export option one can’t really use it for much beyond experimentation today. As long as I’m wishing, a Minecraft import would be a nice feature. I’m sure there’s a few epic structures people would like to print on their shiny new Lionheads without going through Printcraft.

Also, I’d like a pony, but I realize that may be an unreasonable request at this time.

One big plus in Radiant Fabrication’s favor: their email communication with me has been solid. I’ve been pinging my questions and bug reports off them all week and they’ve been ponging helpful responses back, which bodes well for their future as a 3d printer/scanner vendor. Together we squashed a couple of irritating OSX 10.6 bugs, so the software’s in better shape than when it was first released.

One thing I learned during my conversations is that one can hold down the Alt (option on OSX) key during startup and get this configuration dialog.


Check out the “PLAY!” button. Radiant Fabrication could have put any number of words into that button. CONTINUE. NEXT. PROCEED. OK.

But they chose PLAY, with an exclamation point. That gives me an idea of where they plan to go with their product line. They want kids to have fun with 3d printing. Grab a toy, scan that toy, tweak that toy, print a new toy.

This could work. It really could. I’m excited to see the next step on Radiant Fabrication’s thousand li journey.

PowerEx Maha MH-C801D AA/AAA Battery Charger Review

TL;DR Summary: The PowerEx MH-C801D AA/AAA battery charger is easy to use and worth the higher price tag over a dumb charger. The LCD screen can be a little difficult to read, especially under low-light situations. Don’t believe the marketing photos when it comes to readability.

Last week, the lovely and talented Mrs. Zheng3 suffered through a night of fitful sleep brought on by the pathetic hourly chirping of a dying pager desperately trying to suck the last few electrons from its poorly-charged AA batteries.

It’s my fault, really. For years the battery charging duties in Zhenghaus have been attended by a venerable Die Hard battery charger. McClane, as it has come to be called, is what the Folks Who Know About Such Things call a dumb charger, which means he’ll just sit there and keep pumping juice into an already charged battery, shortening the lifespan of the cell.

I’ve got dozens of rechargeable AA’s of various stripes here in Casa de Zheng, from my pricier Sanyo Eneloops to the afterthoughtish Amazon NiMH’s. They’ve seen service in myriad devices, droids, cameras, and controllers and every now and then we find one in pretty sorry shape. They can’t seem to hold a charge for very long.

The lovely and talented Mrs. Zheng3 put at least one of these duds into her pager before hitting the sack. You can’t tell just by looking at it that a battery’s going to suck.

So upon waking for the eighth time in eight hours, the lovely and talented Mrs. Zheng3 looked deeply and lovingly into my eyes, held my hands, and, in that sultry and slightly haggard way she has after a restless night, like a naiad who bleary-eyed sipped too many mimosas with the sylphs and dryads in Elysium the night before, if that naiad was forced to carry a pager for work by her out-of-touch IT department, with pursed and waiting lips, gently, ever so gently, told me to buy a new f***ing battery charger.

Amazon Prime saves marriages. You read it here first.

How much of a charge any given AA has in this house is always an age-dependent crapshoot. Here’s hoping the PowerEx MH-C801D can bring some of them back to reliability. It’s got a conditioning mode that might do just that.

PowerEx MH-C801D: Die Unböxenung

The back of the box for the PowerEx proudly advertises that the battery status updates are “in English.” This feels like a sop to crochety dudes who are upset that the buttons on their phones are too small and that the Monkees are three times the band One Direction will ever be because at least the Monkees played instruments and didn’t prance around like strippers for crissakes. The rest of us learned to accept Engrish as the lingua franca of technical manuals in the 80’s. For great justice.

Here’s what comes in the box:


A charger, a power brick, two cables, and (pictured below) a plastic case that looks like it’ll hold 8 AA’s. Ten points to Ravenclaw for including non-polystyrene fill in the packaging. Also not pictured are a double-sided single page instruction sheet and a glossy promotion for PowerEx’s other products.

The product feels sturdy enough, and the power brick’s LED glows green like wyrmwood when it’s plugged in. It’s a nice variation from the blinking blue LED constellation up in this humpty-bump.

PowerEx MH-C801D: Das Batterieladenungenschlaft

(My German’s pretty rusty, but I think it’s safe to just make words up by stringing loosely-related concepts together. German’s the Human Centipede of languages.)

The instructions (in English!) for the MH-C801D indicate that conditioning can take up to fourteen hours. I have this thing with new electronics. I don’t like to leave them plugged in for too long without supervision. At least, not at first. So I set the battery charger up in my bedroom with the idea that the smell of burning plastic should rouse me from my melatonin-fueled catatonia before the house burns to the ground.

The UI for battery conditioning is an artifact of the consumer electronics design process. Keeping costs down requires engineers to use hardware without adding fancy gewgaws, so it’s insert a battery, press and hold the (cryptically labeled) conditioning button within 5 seconds, wait until the LCD screen displays a very tiny “condition” indicator, and then put in the remaining batteries.

My coffee maker’s like this, but worse. I can program a homebrew robot that turns photos into Etch-a-Sketch drawings, but I can’t program my coffee maker to brew coffee before I wake up. I’m really looking forward to the day when Siri-like assistants are cheap enough to be included in Happy Meal toys. I guarantee that I’m going to forget how to do this the next time I condition a battery, likely six months from now.

The LCD tells me that I’ve got a range of battery charges from the handful I popped into the charger, and the conditioning process begins with an initial charge. The display’s a little faint, so I have to get all up in its grill and squint at the indicator.

After an hour or so battery slot 1 has fully charged, and slot 6 has already begin to discharge.


And just before bedtime the recharge process has begun in slot 6 while the other slots continue to discharge. The aforementioned conditioning button is on the left side of the unit.


Sometime overnight everyone got topped up, and the charge is done. Also, I didn’t wake to a raging inferno, so the unit passes the new electronic-gizmo-kill-you-in-your-sleep anxiety test and is now a welcome member of the household.

Every AA I can find in the house gets a conditioned replacement, which means I have a new passel of batteries in need of love. No problems, and a day later I have another eight conditioned AA’s to put in my new plastic case.


Take a look at the right side of the box and you’ll see that it can hold AAA’s as well, if they’re inserted crosswise. The MH-C801D can recharge and condition AAA’s too, I just didn’t have any around that I could use to test this feature.

PowerEx MH-C801D: Die Rindfleischetikettierungsüberwachungsaufgabenübertragungsgesetz

I still have a few AA’s left over that have been neither conditioned nor recharged, so I shall attempt a rapid charge. This is the default mode for the PowerEx, just drop your batteries into slots and wait. It should take about an hour.

The instructions warn that the batteries may become hot to the touch during a rapid charge. How hot? Not hot enough to be uncomfortable to the touch. Not snuggly, but not uncomfortable, and you shouldn’t be snuggling with batteries anyway, you pervert.

Note to self: buy and review one of those thermometer guns Gale used on his teapot in Season 3 of Breaking Bad.

Thankfully the designers resisted the urge to make the charger chirp or blink when it’s done, unlike some products I could name. Sometimes the features that don’t make it into a product are as important as the ones that do.

The lovely and talented Mrs. Zheng3’s pager hasn’t chirped once since the battery swap, so I think we can call this one a success. Go out, grab one of these, and ensure domestic tranquility and equitable charge distribution in your home. In English, or whatever language flöatzens your böatzens.