Wednesday, October 19, 2011


Say goodbye to unsightly STL triangle misery! Forever!

I downloaded Rupert Rawnsley's OpenSCAD Horizontal Spool Holder from Thingiverse and  printed it on one of my Prusa Mendels.  Nothing unusual about that.

Except that at no point in the making-chain from Thingiverse to the finished printed object was an STL file used to do the calculations.  The spool holder was printed directly from OpenSCAD's CSG representation.

Printing directly from CSG is much more robust than using the flakey (literally) STL file format.  A CSG file can be wrong - we can all make mistakes - but, unlike STL, it always represents an unambiguous solid.

It should also be faster.  I'll do some timings and post them later.  Finally, it should allow us easily to do fancy things like filling solids with scalar and vector fields representing build parameters, so you can have an object that is flexible (and/or green) at one end and rigid (and/or blue) at the other.

I built a simple CSG modeller into the RepRap Java Host Software.  I added a parser that directly reads the CSG generated by OpenSCAD into it.  (The software still uses the STL too, but just as a bunch of triangles for display on the screen; STL takes no part in the build process.)  At the moment the supported OpenSCAD primitives are cubes, cylinders (including frustums and cones), and spheres. I will add extruded polygons, extruded imported DXFs, polyhedra, and imported STL files later (in that order, which is also the order of difficulty of doing them...). Note that the final one of those will implicitly (there's a mathematical joke there somewhere) allow any STL file to be converted to CSG.

Just like the CSG processor at the heart of OpenSCAD, the software is essentially a re-implementation of my old friend John Woodwark's DORA CSG modeller (Divided Object Ray-tracing Algorithm) from the early 1980s (see here).

For instructions on how to use all this, follow this link...

Stop Press: 

Marius has just upgraded OpenSCAD to make things even easier.  The OpenSCAD Github master now has:

$ openscad examples/example001.scad -o out.csg

..or Design->Export as CSG

Friday, October 14, 2011


RepRap Meeting in Bath

If you're in the Bath/Bristol area of the UK at the start of November and would like to see RepRap and hear a talk on it, why not come along to this:

It's free :-)

Thursday, October 06, 2011


3D Systems Print Quality Mixup

Above is an enlarged image from 3D Systems Botmill Branches Flickr account.  Do you notice anything strange about the build quality of that part?  It was NOT printed using the wades extruder above it.  This was a fun catch by Prusajr while visiting the United States for Maker Faire and the Open Hardware Conference.

3D Systems makes some wonderful machines, the printed part on this RepRap did not come off a extruder based 3d printer.

I thought maybe someone not related to 3D Systems had just set it there, but when I went back and looked though their official website, there it was on their Flicker Page.

Note: I contacted Cathie Lewis, the VP of Marketing for 3DS and she said confirmed that part did come off one of their Personal 3d Printer and was an unintentional mix up by one of their employees that was corrected by the 2nd day of the Maker Faire.  I only posted this so that any of the people at the Maker Faire who saw the part would not be confused.  We are not quite there on the print quality, but we are getting closer every day. :)

Wednesday, October 05, 2011


Still Extruding: Catching up

Many apologies to the people that find the series helpful, I had a family emergency, and a a work change that threw my tutorial stuff out of wack.  I have about 10-12 video to upload, so as not to overload folks I will be uploading them 2 at a time here.  Please if you find issues in the video comment in the video, but if you have questions go to the RepRap IRC.

While doing tech support I find a lot of peopel are intimidated by the idea of altering firmware.  That's understandable, when I started I REFUSED to change it for fear of destroying something.  The 3 big firmwares for RepRap right now Sprinter, Marlin, and SJFW all use basically the same configuration.h file based off Sprinter.  I hope this makes firmware alteration a little less scary.

Powering a RepRap from an ATX is really not that hard, but for a lot of folks it can be quite confusing.  I should have edited this video down, but I find that a lot of times it's the little things that seem to throw people off on this one.  The Yellow wires are the 12+ line and for the most part the only one we use.  If your going to power something like a HBP you need to power it off 2 legs at once, the easiest way to get 2 legs is to find the square 4 pin plug with 2 yellow and 2 Black, each of those yellow should be on separate legs and make it (hopefully) strong enough to survive a Heated Build Plate.  Strip both yellow and black wires, twist them about themselves and attach them to the 11 amp connector on your electronics.  Everything but the HBP can be ran off 1 leg, best way to find 1 leg is just grab the 4 pin Molex connector and connect to the 1 yellow (12 volt) and the 1 black (ground).

Again if there is an issue with the video, comment on the video so I know I need to reshoot it, but if it's a technical question, go to the RepRap IRC for our free 24/7 Tech Support/Bazaar/Robot Support Group.

Saturday, October 01, 2011


Hear Adrian Bowyer on BBC Radio

Adrian is interviewed by Shaun Ley about RepRap on Sunday 2 October on the BBC Radio 4 news programme The World This Weekend.  The interview will be transmitted sometime between 13:00 and 13:30 UK time.  You can listen on air or on line.  The programme link is here:

The World This Weekend

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