Welcome

This page is about my interests, projects, and profession (technical artist in the video games industry).  Most of my hardware\software projects are coded in PythonProcessing, & Arduino.  I also enjoy 3d printing, you can find my designs for download over on Thingiverse.  I’d be happy to print for you via the link on the right –>

Find Processing\Android\Python programs\apps I’ve developed via the above title bar.

I also maintain several wikis on Maya\Python\Pygame\Processing that I update far more often than this blog.  See them on their page.

All information on this site is copyright under the Apache Licence v2.0, unless otherwise noted.  Which means you can pretty much use the information here for whatever you like, but I always appreciate credit where applicable.

Have a look around.  Thanks for stopping by.

– Eric Pavey

3D Printing Cars In Carbon Fiber PLA

For Christmas I received some Carbon Fiber PLA from Proto-Pasta.  I’ve been trying to figure out what to print with it, so I settled on the Strati, the ‘3d printed car’ from Local Motors: They were cool enough to upload the stl’s for it to Thingiverse.

strati_filter

Sliced with Simplify 3D.  I had a heck of a time getting it to print however:  To get success, I had to increase my layer thickness to 300 micron (from 200) printing at 220 deg @ 90mm\sec.  I reached out to their support, and they were prompt to reply with suggestions.  I look forward to printing more with it, the finish quality is really cool, almost like 3d-printed coal.

Review: Mk8 Extruder Nozzle by AVN Swiss

I recently realized I’ve had my Makerbot Replicator 1 for nearly three years now, and never once put a new extruder nozzle on it.  Oh, I’ve removed and cleaned\unjammed the current one many times, and over the years the filament has been extruding slightly… crooked as it comes out of the nozzle.

Turning to the Makerbot Users Google Group, I asked what people used as a replacement source.  AVN Swiss commented they sell them on ebay, and I’m a big fan of buying American, so I thought I’d give them a shot.  Shipment showed up promptly.

Full disclosure:  They did ship me some extra nozzles.

They look great, especially compared next to the old crusty guy:

old_and_new

Easily installed into the heater-block:

new_installed

Extrusion is nice and straight.  It’s bending to the right simply because it’s pooling on the build platform.

new_extruding

First layer of 20mm calibration cube is flat and even:

first_layer

Final result is smoother than this shiny black PLA makes it look.  Stopped the print to show off the layers.

calibration_cube

Overall I definitely recommend them as a buy: Worked as expected, promptly shipped, and made in America.  What more can you ask of an extruder nozzle?

Portable Kinect scanning

protable_skanectI’d done a few experiments in the past with the Kinect / Skanect software (here, here).  The biggest issue (other than my underpowered Macbook Air) was that you’re tied via the USB cables to both the computer, and the electrical socket in the wall:  Hard to walk around things to scan them.

After looking at the wall-wart for the Kinect, I saw that it works off 12v DC:  Based on that, I picked up a small 12v Tysonic battery from Jameco, cut off the wall-wart, and soldered in some alligator clips to the power-cord.  Now the Kinect clips directly to the battery (which fits in my pocket), allowing me to hold the Kinect in one hand (based on this sweet 3d-printed grip), my laptop in the other, for completely untethered scanning.

So while it is still way more clunky than an iSense/iPad combo, that battery only cost me $15, and I got the Kinect used for $50:  A slightly lower price-point than a iSense/iPad purchase ;)

Making (real) aluminum boats in Maya

render_persp

Maya render of the boat

pops_bro_boat

Current state of the boat, with my father and brother.

My father has been building boats since before I was born and running them on the rivers of Alaska:  Fiberglass canoe?  Check.  Flat-bottom wooden riverboats with dual outboards?  Check.  Should I mention the hovercraft? ;-)  Over the past decade he’s branched out into welded aluminum flat-bottom riverboats with great success:  Make one, use it for a few years, sell it and make an upgraded version.  (On a side note, I can’t wait to retire… <wink>)

Late last year he came to me wondering if I could help with the design:  Could I create the 2d design files he would provide to a local plasma-cutter to cut the main boat forms?  Sounded like a good challenge, and a great opportunity to collaborate with my father (He’s in AK, I’m in CA).  Up until then he’d get the huge sheets of aluminum and cut them by hand.  Having a plasma-shooting robot do that sounded like a more exciting (+ accurate/faster) solution.

My father provided me the drawn plans with angles and dimensions:  I started the process of turning those into real 3d forms.

Initially I attempted to do the whole project in Autodesk Fusion 360:  I’d been teaching it to myself, but I was still very much a noob in the software.  Unfortunately I just couldn’t get it to do what I wanted:  Most importantly I couldn’t ‘unroll’ the 3d forms to 2d forms, which is needed for plasma cutting.  I worked directly with their support on this, but the software just wasn’t quite there yet.

So I decided to do it all in Autodesk Maya (which I’ve been using since it was released in ’99).  While Maya is great for games\film\vfx, I’d never much considered it for accurate CAD-style modeling.  However, it ended up working great. Here are the main takeaways on how I built the boat:

The initial boat model:

  • I started by modeling the real-world size sheets of aluminum out of NURBS planes.
  • I snapped and rotated the pieces together to get the overall shape of the boat based on the provided angles.
  • I applied bend deformers on a single axis to shape the NURBS into the correct swept forms.
  • Based on all the intersecting NURBS, I created curve-on-surface intersections:
intersectingNurbs

Right side bent NURBS intersection, with curves-on-surface, before trim.

  • Based on those intersections, I trimmed away the excess aluminum (NURBS).
  • Boat model complete! (see above render)

The unwrapped form:

  • I needed to ‘unwrap’ all the bent surfaces back to flat planes for export.
  • To do this, I would duplicate each of the bent/trimmed NURBS, convert them to polygonal mesh, and wrap deform the polys back to the original bent NURBS.
  • On the original, I’d access the bend deformer, and zero it:  This would flatten out the wrapped polys.  I’d delete history on the polys, leaving it flat, then bend the original piece back.  I’d then scale it perfectly flat, since the wrap wasn’t 100% accurate.
  • I’d repeat that process on each bent piece, ultimately giving me unwrapped flat pieces for all parts of the boat:
unrolled

Unrolled polys

Exported 2d data:

  • I exported each polygonal mesh as obj.  I then used online software to convert the obj to pdf’s, which the plasma cutter could use.

After my father got the 2d data he printed a scale model on paper, affixed it to poster-board, and made a small-scale mockup as a sanity check:

paper_boat

 

From there, it was off to the plasma cutter…

And the most amazing part?  It all worked:  After my father got the pieces back from the plasma cutter and starting tacking them, they all fit perfectly.  Sighs of relief on all sides.

While it’s been fun to 3d print small items, it was super rewarding to see a much larger-scale 3d model become reality, and do some ‘real’ work with my father.  I can’t wait to ride in it!

New Project: Adafruit Trinket NeoPixel LED Longboard

My son and I recently tackled the “Adafruit Trinket NeoPixel LED Longboard” project: Seemed like it would be a good cross between 3d-printing, electronics, and skateboards.  After running through it though, I found a number of problems with the instructions which I submitted here (if you’re going to do this project, be sure to read them).  Unfortunately at the time of this authoring they haven’t updated their project page to address the problems.

In a nutshell, this is what you need to look out for:

  • Need to order two Neopixel LED strips, not one.
  • There are problems with the wiring instructions, based on missing data.
  • Unless you have ninjaflex or nylon, you may want to entirely skip printing/assembling the front ring enclosures:  I printed mine in solid PLA, and they vibrated apart after the first ride (snapping the internal wiring in the process).
  • If you do print the rings, you really do need to use “wire wrap” to do all the wiring:  Larger gauge wire just won’t fit based on the printed models.  The problem I have with this is although you only need a small amount of wire wrap for the project, it’s best if everything is color coded, and buying wire-wrap in multiple colors actually gets a bit expensive.  I ended up using just two colors, and having to label all the wires (which pretty-much makes it impossible to fix if they snap after everything is assembled).

Overall it was a fun project, just seriously hindered by the confusing instructions, based on other issues I list in the above link.

Here’s the end result before the rings fell apart (and I removed them).  Note the metal bracket over the electronics enclosure and front of the  skateboard:  One jumped curb and you’ll have some smashed equipment without it.