Re: [rp-ml] algorithm&implementation for STL slicing-SplineScan

They are relatively common. From a quick search on "laser scanning head cnc
mill":
http://www.kreon3d.com/products_zephyr.php
http://www.omnicmm.com/probing_equip.htm
Many links:
http://www.simple3d.com/#laserscanner

-Sebastien

On Friday 25 August 2006 13:51, you wrote:
> I keep wondering why someone does not adapt a project like this to make
> a non contact scanning head for CNC machines. Off the cuff it would
> seem that you could create a hardware head that would sit in a collet
> holder and software that would output generic G-code to scan an
> arbitrary sized area. Is it more difficult to patch meshes where the
> scanner is moving rather than the part?
>
> Charles
>
> Sebastien Bailard wrote:
> > On Thursday 17 August 2006 19:01, you wrote:
> >> At 4:25 PM -0400 8/17/06, Sebastien Bailard wrote:
> >>> For raw 3D structured light scan to stl , there is some open source
> >>> software called http://splinescan.co.uk/ . (This is the opposite of
> >>> what you are asking for, as far as I can tell.) It is GPL'ed python
> >>> code.
> >>
> >> Hi Sebastien,
> >>
> >> Thanks for all the info! Splinescan looks interesting and fun - I may
> >> have to give that a try.
> >
> > Do. If you need support, you'll have to get it through the splinescan
> > mailing list. The lead developer's working on development, not
> > documentation just now, but someone should answer. I have no idea when
> > they're going to publish their next release.
> >
> > They've got some interesting tweaks in the pipeline - they're going to
> > publish a hardware package that you can RP, so all you have to do is
> > assemble it, bolt on a camera, laser pointer diode, cylindrical lens
> > (glass rod), and you've got the scanning unit. For the turntable, just
> > go scrounge a turntable and have your laser printer print out a paper
> > encoding strip*, paste it on, and you're good to go. The camera/python
> > code figures out where the turntable is by looking for the encoder strip.
> > http://www.hitl.washington.edu/artoolkit/
> >
> > I've been daydreaming that all you need is a sheet of paper printed with
> > artoolkit tags and a camera, and you could put an object on the sheet,
> > take loads of photos, and then dump them into gpl'ed code that figures
> > out all the computational geometry and spits out your point
> > cloud/simplical surface/.stl file. It would take some keen programming
> > and computational geometry, but it would be so useful.
> >
> > If you happen to be interested in the computational geometry background
> > for all this, look at "Surface Reconstruction from Unorganized Points" by
> > H. Hoppe et.al. 903 citations, and fairly readable,
> > http://scholar.google.com/scholar?hl=en&lr=&q=Surface+reconstruction+from
> >+unorganized+points&btnG=Search
> >
> >>> Roy - what materials are you working in? You may be able to use our
> >>> extrusion head along with the control software:
> >>> http://reprapdoc.voodoo.co.nz/bin/view/Main/Version2OfThePolymorphExtru
> >>>sio nHead
> >>
> >> I've been aware of Reprap but didn't realize or look closely at the
> >> software part of the project. have to take a closer look. My materials?
> >> Well... this is a 'for art' project so I have been looking at various
> >> materials which flow and then harden - slurries of clay, etc. I was
> >> thinking about wax but wanted to avoid the complexity of a heating
> >> element.
> >
> > I would go with kaolin slurry or store bought "earth clay" slurry or slip
> > as well in that case, or cncmill/RP a reprap extruder head and use
> > thermoplastic. It'd be a lot easier to set up.
> >
> > Waxes can be nasty - one tuft of cat hair in your feedstock, it clogs,
> > and unless you've got a thermostat or thermal-overload detector and hard
> > shutdown circuit, it all goes up like a candle and you kiss your studio
> > goodbye. So many artists die just because they forgot to use a double
> > boiler, crockpot, or soup warmer to heat their wax, so they just put it
> > directly in a pot on the heating element, maybe go and answer the phone,
> > the bottom layer liquefies and starts to boil even though when the top's
> > solid, then you get a big cloud of vaporized wax and poof! Wax is the
> > main reason art foundries and studios burn down, so you'd want to trouble
> > shoot the hell out of any autonomous 24/7 mechanism you're building that
> > uses wax. A slurry printer screws up, and all you've got to clean up is
> > a puddle.
> >
> > One thing to realize is whatever earth clay you go with is possibly going
> > lose all its plasticity if you run it through a feed system - it depends
> > how happy the bacterial colony is in the clay, after it's been extruded.
> > (Bacteria makes the gel that lets the clay platelets slip past each
> > other.) But a couple spritzes with dilute vinegar could perk it up again/
> > http://www.potters.org/subject37221.htm
> > If you're not going to work the clay after extruding it, this doesn't
> > matter.
> >
> > You might be able to use a good oilclay (aka plasticine, modeling clay)
> > instead of wax. Oilclays liquefy when heated, but I don't think they can
> > burn.
> > http://www.sculpture.net/community/showthread.php?t=1884&goto=nextoldest
> > One problem with oilclay is you can't sell it as a finished piece without
> > going through the casting/moldmaking steps. Wax or thermoplastic you can
> > do lost wax casting with, slurries you can fire in a kiln.
> >
> >> For a 'print head' I have been tinkering with building a peristaltic
> >> pump - the idea being that with that I can deposit a measured amount of
> >> material that is fairly viscous and it seemed a simple way to do it.
> >> It's all in the testing/failing stages now.
> >
> > Sounds fun. Did you see
> > http://reprap.blogspot.com/2006/07/peristaltic-pump-go-after-all.html
> >
> > Think you can clip one onto your 'Drip Painter' machine?
> >
> > Apropos of nothing, we're using wood filler for a test material. It's
> > pretty much wood glue (polyvinylacetate) and marble dust.
> >
> >> I'm assuming (and hoping) that this will be a functional "expressive" 3
> >> printer - along the lines of Giacometti type forms. I think I can get a
> >> fair degree of precision in placing the material- and the material will
> >> slump and distort in unpredictable ways. The art/sculpture "part" of
> >> this is both the machine as it's working and the forms it creates.
> >>
> >>
> >> --Roy
> >
> > It's an interesting approach. Sort of like manipulating the hell out of
> > the negative in the darkroom, where I'm stuck on photorealism/toolmaking
> > - I want to image an oilclay model or broken machine part, work up the
> > virtual image, print it, and have a perfect duplicate.
> >
> > How are you planning on creating your input code - c code that bit bangs
> > the printer port and the motors do their thing, traditional cad cam -> g
> > code -> emc (linux machining controller - linuxcnc.org ), or something
> > esoteric whipped up in processing? (algorithmic art / data analysis tool
> > with thriving community - http://processing.org/ ,
> > http://www.pingmag.jp/2006/03/31/processing-maths-to-art-in-one-simple-st
> >ep/ )
> >
> > Regards,
> >
> > -Sebastien Bailard
Received on Fri Aug 25 22:03:39 2006