Today was a nother very busy week in terms of awesome things, with the Biometrics cluster acquiring a few new goodies, with a few new everyday things like tarp pins, two flavors of wall clock and a hairclip, and in the realm of Fab Science, there’s a RepRap add-on,  a gear script and even DXF files for a makeable motor, and with this kind of cornucopia to choose from, I kind of had to go with one of the classics, the Utah Teapot.

I used to do ray tracing on my parents’ 486 back in high school, so I’ve definitely met this beastie before.  The current version’s no good for tea, but probably soon there’ll be a manifold pot-and-lid pair, and with the UW’s 3D Clay Printing process and maybe a bit of glazing, I may not be far from making actual tea in an actual Utah Teapot.

Needless to say it will be one of my more gleefully geeky moments all week.

In addition to the many wonderful stl and dxf files on Thingiverse, there’s a growing number of scripts which, instead of creating one exact shape, can be reconfigured to create a family of shapes for each script.

The Box-o-tron represents not one box but a whole class of boxes.  The GCode Python Packs turn math into models.  There’s now a script that makes detailed, correctly-shaped involute gears.  In creating this universe of things first imagined by Zach and the gang, users are discovering how to spend their design efforts making not single things, but whole classes of things at a time, making shapes available to Thingiverse in quantity and richness that really might start to look like the “just download one” future we optimists go on about.

Running out of things I know about Skeinforge– once I get the other post on the Raft dialog I think I’ll switch gears and do some scripting tutorials.  (Anyone who’s got useful tutorials for Skeinforge, Blender, or other digital fabrication design tools, let me know in comments and I’ll see about putting it up some Tuesday.)

But about the Cool dialog.  Checking enable cool and setting the minimum layer time will cause the print head to “orbit” around the printed area rather than immediately printing the next layer.   Skeinforge has M-codes for turning a 3D printer’s cooling fan on and off, so if you’ve installed one on your printer, clicking both “turn fan on” and “turn fan off” run the fan only during orbit times, which is good because constantly running a fan pointed at the extruder head can freeze the plastic, leading to failed builds and stripped-filament-related swearing.

Without a fan, this setting can cause trouble if the printed area of a given layer is very small.  The purpose of orbiting is to get that hot extruder nozzle away from a new layer for a while, but if the area in which the head is orbiting is tiny, the nozzle actually never gets far enough away for the plastic to freeze, and meanwhile is twisting the plastic into a crunchy helix.  (Anyone have a setting that makes the orbit the same size as, say, the raft?  That’d really help…)

Bre shows us some really excellent robot skulls (note actuation systems are still so bulky they take up all the space where brain power would go on an organic system!) with servos in them and I immediately thought, “now at those scales, you could do the fiddly bits largely on a MakerBot.”

Sure you’d need springs, and probably would do better buying the eyes separately, but with standard servos and the magic of super-custom-tooling provided by 3D printing, I’m pretty sure animatronic machines are easily a possibility of personal 3D printing.  3D printing has another advantage though.  3D printing has the advantage that anything 3D printed has already been input into a CAD tool.

This is really neat in that you can show off your model and even run simulations on it to see it working (Blender’s physics engine is notoriously confusing, but it can be done), but in the specific application of animatronic puppets, there’s another big bonus.

Blender has tons of animation features.

With the right constraints, Blender can do inverse kinematics, combine animations, aid in lip-synch operations and a whole lot of other things.  Blender’s Python API provides an interface that should be able to get anything in Blender out and into the rest of the world.  Properly organized, an animation could be exported to a file, which could then be used to drive any number of servos in the real world.

What would you have then?  Why, you’d have your own little Rock-afire Explosion.

It’d take some pretty impressive software hacking and hardware wrangling to get all the peices made, but I think this one is going to happen, because nearly all of the peices that have to get put together are ones which can do something on their own, without the finished product.  Animatronic skull designs are useful without Blender providing walking instructions.  Blender-to-arduino interfaces are useful without animatronic skulls.  And you don’t need to be working on singing robots to want pre-constrained models for testing designs with servos.

Any one of these things, even without the whole, would also be really seriously cool.

Digital fabrication is getting cheaper from all sides, and Thingiverse now includes design specs for a powder deposition system, pioneered by researchers at the University of Washington!  Like the RepRap, this is a work-in-progress, but the basic technology of using inkjet-inspired systems to glue-sinter powder is super-promising, especially in the realm of getting high-resolution, support-material-required models to print well.

Users who don’t need the robustness of a thermoplastic-printed model, and who need a dpi in the hundreds are better off using a powder-sinter method like this one.  Given that the UW has already invented an open-source powder-and-glue pair for printing ceramics, the future of open 3D printing standards is really, really bright!

One great thing about rapid prototyping and personal fab is the little everyday uses.  Thingiverse user Cliff Biffle (who also has posted an awesome chess set) shows us a quick use that saved a lot of irritation on a shelf installation!

While we’re still using 3D printers as niche fabricators rather than primary manufacturing, I think we’ll increasingly see accessory designs published in association with manufactured products like these shelves.  Soon, there just might be enough users and designers running personal fabrication systems that many products (especially the big name ones) have an associated bundle of printable objects on thingiverse or even the products’ site itself that can be used to extend functionality.

Various factions of widget-makers may be harmed by all this, but I think in the end the benefits far outweigh the costs.  After all, the stated goals of the RepRap foundation are much MORE ambitious on this front…

Fill is a script that handles the interior of a given layer sliced by the carve script.  Objects can be made hollow or filled, or as is most common, somewhere in between.  For these hybrid cases, wall thickness can be adjusted, as well as the density of the internal threading to trade off between speed and strength or between strength and plastic used.

The Extra Shells options create additional lines which trace the outline of each layer, just inside the outer one.  I was never sure which layers were which between “alternating solid layers”, “base layers”, and “sparse layers”, so I keep them at the same value.  Extra layers aren’t necessary for all cases, and in especially light builds, they can be left at zero to print only the outermost layer as a solid line, with the interior of each layer printing only as sparse or nonexistent infill.  (Such builds can be prone to collapse during printing or fragile though!)  Cranking this up to three or so is important to getting good water-tight seals.

Infill options: inside each layer, skeinforge lays down a pattern of lines to fill in the interior of a model with strands of plastic, which may be very light or very dense depending on the settings.  Dense models of course are heavier, sturdier, and take longer and use more plastic.  The Infill solidity ratio is the ratio between the infill pattern and a fully-solid object.  Set to 1, this would solidly fill the inside of the object completely.  I’ve had trouble with setting it to zero for fully-empty builds, so when I want empty builds I just set it to 0.01 or such, which is fairly negligible in terms of plastic inside.  A value of 0.3 or so is pretty good for large, sturdy builds.  The infill odd layer extra rotation rotates the infill pattern every other layer, which at 90 degrees creates a square pattern if line fill is used.

I think the interior infill density ratio is a feedrate setting which moves the print head faster during infill pattern drawing to get lighter strands than the outer wall.  Anyone got a better definition?

The solid surface thickness is similar to the extra shells settings, but for horizontal layers.  Skeinforge makes this distinction because it’s different to have a solid fill pattern than to trace an outline.  This setting should be the same as the extra shells settings for builds with uniform thickness on all surfaces, like dice.  Also, low values for this may result in builds with tops that don’t close up fully (because the fill on the top layers sag into the sparse infill) or bottoms that aren’t fully watertight.

The new Blender version they’re working on is looking seriously badass.

The modeling program has been re-coded from the ground up, and from the look of things, it’s going to be significantly less awful to use.  A lot of the pointers I handed out near the beginning still hold: I don’t think they’ve changed a lot of those oddball conventions, but the genuinely ugly things like the tool jumble and the (frankly, hopeless) button panels are being fixed.

Animation multithreading might not be the most thrilling thing in the world for solid modeling, but the improvements to the modifier stack and the operation stack look like really sweet tools.

Meanwhile, there is a Blender 2.49 release which has a few nice features added like booleans anywhere in the modifier stack and natively supported bolt generation which might actually help solid CG users.  As an occasional user of Blender’s art capabilities I’m really really grateful for the painting tools, but that’s just me.

Thingiverse now has a Pen Plotter Attachment for the MakerBot, complete with a recently-added spring fixture to improve the contact the pen has to the paper!  Since felt pens come in sizes much smaller than the MakerBot’s 0.5mm resolution, using the MakerBot as a drawing tool actually creates a higher-resolution plotter than the MakerBot is a 3D printer.  How much higher?  One step on the steppers driving the XY stage is a mere 85 microns.

Sweet!

To me this is pretty huge news (Fabbaloo found it for me): Ponoko is creating a fabber network. This to me is an absolute thrill.  This will monetize fabricator ownership.  This will decentralize manufacturing.  To me at least, this is tectonic.  And Thingiverse has a big role to play here.

Back in my earlier posts I wondered aloud what the monetized side of the digital fabrication market would look like, when it was being done by individual, local owners of fabrication systems.  This is what it looks like.  It doesn’t look like Kinkos.  It looks like– well– like nothing we’ve seen before.

This is the near future: networks of fabricators covering local areas so that designers and consumers commission objects, perhaps piecemeal from several local owners of fabrication services, and some will be owned designs, with a designer who might be anywhere in the world earning a royalty per unit.  But a lot of them will come from Thingiverse.

Thingiverse and Ponoko’s design-buy system will be complimentary, I’m convinced, with Thingiverse designs earning fabricators money by giving them things to offer to the Pokono network royalty free, and Ponoko designs earning designers royalties with every made object.  Very exciting!