I’ve started a project on GitHub for SuperSkein, the brand-new multiplatform slicing utility written in Processing.  It’s not tuned up all the way yet (note the lumpy print above) but I’m convinced you could get at least decent results even with the current version with minimal tweaking, which is why it’s already gone public.

Right now the feature set is really really limited, but there’s a whole class of models that’d work with a single shell (although they’d be a bit fragile obviously) and which perhaps more importantly won’t slice in Skeinforge.  Also, it’s quite fast and can slice even pathological (>800k triangles) meshes in a few minutes.  It doesn’t do any infill of any kind at this time, so meshes with large flat surfaces will just quietly print as hollow shells, but for organic shapes such as scanned sculptures and 3D characters, this might be the new answer already.

(My next post won’t be about Blender, I swear.)

You can now get Blender 2.53, with the bug fixes I’ve been raving about as an official Blender release which last I checked was very stable and quite ready for prime time.  (They’ve got to fix the Python API and a few other things before this replaces 2.49 as the main download.)

Open Source FTW!

SketchChair from Greg Saul on Vimeo.

This is the tool I’ve been dreaming of ever since we got a lasercutter. So cool! SketchChair!

I am going to fill my apartment with this type of furniture!

Blender 2.5 finally has .stl support!

First, you’ll need a recent build (lately these have been more or less bug-free for me at least) from GraphicAll.org.

To enable exporting (and all the other goodies!) go to file -> user preferences and click the add-ons tab.  One of them is stl io, and once that’s enabled, you’re ready to export STL from the increasingly stable and awesome Blender 2.5!

(I recommend you start Blender then immediately change these settings, then select “Save As Default” at the bottom of the settings, which will make sure you always have these tools handy.  This saves everything about your workspace, so if you have changes you usually make such as splitting the screen, they’ll be saved too!)

One quirk I’ve noticed is that if you scale things in object mode, those transformations don’t “count” towards the stl file.  If you notice you’re not getting the size you wanted, you can hit Object -> Apply -> Scale from the 3D View menu to fix that.

In the latest versions of Blender you can go to file -> User Preferences to select a whole bunch of things, including a new mouse zoom mode that’s a lot more like what you’ve come to expect from other CAD tools, such as SolidWorks.  These options are under the Interface tab of the User Preferences dialog.

Checking the Zoom to Mouse Position and Rotate Around Selection boxes will cause the zoom function (scroll the mouse wheel) to be centered on the mouse position, and rotating the view (click the middle mouse button or alt-left click) will move around whatever you have selected.  (For alt-left clicking in new versions you’ll also have to enable Emulate 3-button Mouse in the Input tab.)

Okay so you’ve got Blender and you’re trying to model something with lots of drill holes and Blender’s solid boolean operations are driving you up the wall.  Meshes hash into mounds of needle-like triangles quickly, and needle-like triangles break the boolean engine.  Nature of the beast, I’m afraid, Blender is a mesher.  And meshers aren’t anything like SolidWorks or OpenSCAD, which can handle hundreds of boolean operations without batting an eyelash.

But let’s say you’re not in love with coding object positions by hand and SolidWorks isn’t in the budget.  Now what?

Subsurface Modifier to the rescue.

» Continue reading “The Subsurface Modifier For Mechanical Designs”

On one of the older entries, Roberto Michel writes:

Digital Fabrication is cool, but can it be used to produce actual parts, not just models or prototypes? Won’t more traditional methods like stamping, forging, or sheet metal fabrication, usually be cheaper for most parts?

To answer your first question, yes!  Digital fabrication has a reputation as something you only do for prototyping for a number of reasons, one of which is that many digital fabrication processes (especially high-detail powder sintering methods) produce chalky, delicate parts that you could easily crush in your bare hand.  Such parts obviously aren’t suitable for anything other than show and perhaps the delicate touch of someone who knows the part isn’t “a real one”.  However, this isn’t true for processes like the RepRap’s extrusion method, which creates sturdy, lego-like parts.  Many other digital fabrication processes can even be used as the starting point for processes which transfer the shape into more sturdy materials, like glass or even metals!

The realm of personal 3D fab presently means plastic parts that can be a bit fragile unless you have your machine well-tuned, but they’re definitely suited for everyday use.

To answer your second question, not always.  The cost of 3D printing scales linearly with volume.  For products where a really large number of parts is profitable, this is a complete non-starter.  But for hobbyists or niche markets, the linear scaling isn’t an issue.  All that matters is how much it costs to get one.  And in the case of a MakerBot or other low-cost extrusion systems, that cost is often on the order of pennies per cubic inch.  Acquiring the specialized molds and tooling for each new object would be prohibitively expensive in this kind of market.  And how small do I mean by niche?  Well, it doesn’t just depend on factory costs.  There’s all that shipping and handling too…

As the overhead cost of digital fabrication (both in money and time) goes down, the definition of “niche” here will widen.  There’s a whole class of everyday objects that can be replaced by existing low-cost parts, and since a 3DP owner using open source, non-lockchipped plastic can undercut the price of even cheap plastic items by cutting out a pretty big army of middlemen, we’re seeing extrusion material start to find its way into a lot of everyday items.  To put it in a short sentence with a lot of buzzwords, digital fabrication circumvents the need for sophisticated supply chains by leveraging ubiquitous computing to create a general manufacturing process at low cost.