Tag Archives: Clothbot

OpenSCAD, ReplicatorG, why can’t we all just get along?

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I need to bolt some shelving to the wall.  Yes, I know the shelves came with some hardware for doing that – but I own a 3D printer and I can design BETTER hardware.  I whipped something up in Sketchup and printed off some brackets.  Next, I needed a slight variation in order to bolt two shelving units to each other.  (Something for which their hardware wasn’t designed).

Unfortunately, ReplicatorG just puked all over itself as soon as I tried to slice the bracket.  I had been tinkering with OpenSCAD for the last week or so, so I figured I’d give that a shot.  Here’s what I tried:

  • First, I tried building the bracket up out of just rectangular boxes.  This was okay, but cumbersome.
  • Next, I tried to design a really really complex polyhedron in the shape of my bracket.  This was a nightmare.  To do it properly, you need to design your object such that you’re defining each of the triangles that make up the object.  If you get set up the triangles by putting the numbers for each corner in the wrong order, in a less-right order, or did some other benign thing, it would make a mess.
  • After chatting with Clothbot, I tried to define a cross section of my bracket as a flat image in Sketchup (again), then tried to expert it to a DXF through a plugin.  I just couldn’t manage to extrude that flat DXF into a 3D image.
  • So, I went back to Sketchup and tried to tinker with the file again, fixed it in CADSpan, exported to STL again, fixed it up with NetFabb again, and ReplicatorG still barfed it up.
  • Back to OpenSCAD (again).  This time I tried to assemble a 2D cross section of other shapes.  This didn’t work as I tried to tinker with the “linear_extrude” function.
  • THEN, finally, I tried to define a polygon (not a polyhedron) based upon the coordinates I had used originally to describe the bracket when I was attempting to build it out of triangles.  This worked to describe a flat 2D section of the bracket.  I tried the “linear_extrude” function again and it worked well.  I then punched a few holes into the bracket with some small cylinders and exported to an STL again.  It’s my understanding that OpenSCAD makes quality STL files – without holes or other cleanup required.  While that may be the case, you guessed it, ReplicatorG tossed its cookies when it saw this bracket.

So, what is it? Is it the bracket?  Sketchup and ReplicatorG?  Is it OpenSCAD?  Suggestions?

Clothbot’s distillation of OSHW

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I really like Andrew Plumb‘s distillation of the Open Source Hardware (OSHW) Draft Definition version 0.3.  I’d hate to see it get lost in Twitter history, so here it is:

  1. Documentation: Establish & facilitate the right to repair.
  2. Necessary Software: Operates using Free Open Source Software.
  3. Derived Works: The right to fork the project.
  4. Free Redistribution: Pay for parts, not permissions. No restrictions on the sale of parts.
  5. Attribution: Give credit where it’s due.
  6. No Discrimination Against Persons or Groups: Respect is earned.
  7. No Discrimination Against Fields of Endeavor: Make recommendations, not restrictions.
  8. Distribution of License: Share Alike.
  9. License Must Not Be Specific to a Product: The right to re-use.
  10. License Must Not Restrict Other Hardware Or Software: Play well with others.
  11. License Must Be Technology Neutral: The right to modify.

Edit:  See more amazing distillations, machinations, imaginations, and mastications at the Clothbot wiki!

Dremel Flex-Shaft Mount

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I don’t own a dremel1 but I particularly like Andrew Plumb / Clothbot‘s Dremel Flex-Shaft Mount for the MakerBot.  This thing will turn your MakerBot into a mini-drill press or mini-CNC mill.  But that’s not the reason I like it.

I like this thing because the design is totally functional and completely nuts.  It’s just not the kind of thing you’d ever find in a store.  And yet you can just whip one up in about half an hour with a MakerBot.  Amazing.

  1. Yet [↩]