Slicing workflow for Lasercutting (Glowforge)?

Hi all
I’ve been blissfully using Rhino to output STLs for 3D SLA printing to envisionTEC and B9 Creator printers. Each have their own included pre-printing utilities for slicing the STLs. Pretty straightforward and familiar territory there. Time to go outside my comfort zone…

I’m in for one of the Glowforge laser cutters ( http://glowforge.com/referred/?kid=tCTeUI ) due next year and have been looking at the various 3D software to use with it.

Some initial searching in this forum regarding lasercutting seem to be focused on posts about extracting surface facets. That’s not what I’m after.

My intent is to slice a 3D nurbs model, bring the 2D images to the laser cutter so that the cut physical layers can get re-assembled. Ergo this thread. IOW, something more akin to stereolithography assembling with cardboard/wood/plastic layers as opposed to micron-scale cured resin printing.

Rhino’s SLC file export comes close, but not one of the Glowforge compatible formats. Any chance the SLC plug-in could be tweaked to output a series of SVG outlines to a folder? Various machines and processes out there could more immediately use SVG over SLC, it’d seem to me. (ie, 2-dimensional SVG slices could be used for importing into AfterEffects/AppleMotion for visual effects use)

Thanks

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Not sure, but maybe this plugin can help - RhinoNest

Thanks cadmaster. The clip certainly shows the slicing, but whether it’ll save to a more universal 2D format is preempted by its $1100 pricetag.

With some further searching, I’ve come across this Grasshopper script:

Seems to be the strongest candidate so far.

Typically the gas has to be replentished with cutting lasers after a certain amount of use. Does the unit have to be sent back in, it it user replaceable, or perhaps it uses a different laser technology?

I see now that its using a CO2 laser, so at some point the gas will be depleted. Curious there is no estimate of hours of use.

If I recall, it might’ve been mentioned in one of the clips:

Tested’s first clip

Follow-up interview

TechCrunch’s interview

MakerCon presentation

Back to the subject at hand, I’d really love to see the workflow of how current lasercutting users are working with Rhino. Layer-stacking is one technique, but briefly thinking about other things I’d like to make, I suppose I’d still want to use Rhino to model and extract 2D lines (as opposed to designing in Illustrator)

Maybe try export dwg or dxf from Rhino to free DraftSight end then export svg from there.

@CarterTG Have you tried SectionTools for Rhino ()?
http://wiki.mcneel.com/labs/sectiontools
It is a free plugin from McNeel. Here is one tutorial to show how it is used for laser cutting:

Overall, it seems like a nice package. Its not that expensive considering the entry point for other small cutting lasers has been 10 - 15 K or so, so even if you had to replace the whole thing every few years, it might not be a bad option.

Back on topic, if you anticipate having to do notching it might be worth looking at 123Make (the paid version allows commercial use). Sure the notching could be done in Rhino, but it appears to have built in notching functions, as well as layout/nesting.

I admit, I haven’t tried it myself, but I definitely have to give it look.

I have an older script for slicing which I will attach below for reference - it works OK, but I do need to update it sometime…

What I tell my students to do is rather simpler, takes 30 seconds and doesn’t require any scripting:

  1. Use the Contour command with a vertical line reference to create slices. Make sure you have group by slice level set to yes if your object will produce multiple slice curves per level (like if it has holes in it). Leave the slices selected after the command finishes.

  2. Make sure you are in 4 view or you can at least see both Front and Top views at the same time.

  3. From Front view, start the command Shear, again create a vertical line reference with two points. Make sure Ortho is inactive, then simply pull the slices over to the right by rotating the shear reference line counterclockwise. While doing this, look at the Top View and see how the slices separate, when they are completely separate as seen from the top, click in the Front view to “set” the shear. You may need to zoom out significantly in Top view to see all.

  4. To finish, with the sheared slices still selected in top view, call ProjectToCPlane. Your slices are now flat on 0.

  5. The “manual” part is to number and organize the slices into rectangles representing the sheet sizes you can cut…

It actually sounds much more complicated than it is to do.

–Mitch

SliceNFlat.rvb (9.4 KB)

@Rajaa & @nick : Thanks! Sectioncut and Contour commands do the trick! Working with Rhino is like living in a comfy home only to occasionally discover a few more additional rooms never seen before!

@Helvetosaur : Thanks Mitch, I’ll look into the script if I start hitting some limitations on the previous commands

The only remaining workflow gap is being able to output to a more updated set of formats when it comes to 2D curves. DXF is there, of course, but it’d be nice to have SVG and EPS.

You found that Grasshopper solution but also look at this thread:
http://discourse.mcneel.com/t/export-to-svg-challenge/25618/9

Only marginally related to the topic at hand… (this Glowforge topic was interesting and led all sorts of places…)

Lasersaur is modeled in Rhino.
http://www.lasersaur.com/manual/model


https://vimeo.com/35907501

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Check this out.

Not native to Rhino but it will slice your part and give you a 2D layout on the sheet size
you want as well as calculate thickness of layers. It numbers the layers as well and will even
give you a video of how to assemble your parts. But wait there’s more! Watch the video!

I do this kind of slicing all the time for sculpture fabrication, and I have a couple of scripts I use for different workflows.

I start by generating contours from the 3D model at the required thickness (e.g. 3mm, if you were making the model from 3mm plywood). If the original model was not watertight, I may need to do some manual cleanup on the contours.

Then, in the “Top” viewport, I add a template for part labeling; this is a Text string of the form “MyObject###”, which will result in each individual part being labeled as “MyObject001”, “MyObject002” etc., starting from the bottom contour.

CuttingDrawings.rvb (6.1 KB)

This one is for generating parts for CNC fabrication, and is probably what you want. It will ask you to select the slices (i.e. your cutting outlines), and then it will ask you to select the label template, which is optional. Finally it asks for the slice height, which should match your contour interval.

The script will output a flat sheet of layers, with each separate piece nested and labeled according to your template. The nesting is not very sophisticated-- I use my CNC software to re-nest the sheets much more efficiently before cutting-- but in principle this 2D drawing is ready to export as DWG or whatever and laser cut. The script renders the labels as lines and puts them on a separate layer, so you can easily get your laser cutter to etch them rather than cutting all the way through.

NOTE: the script relies on you having this font installed

ExportSlices.rvb (4.0 KB)

This script is a little cruder; I use it to generate PDF files, showing one layer on each file. I use it (a) to generate reference documents to help people assemble large sculptures and (b) to be projected onto sheets of styrofoam which are cut out by hand to make large, rough molds for casting. If anyone wants to use it and can’t work it out, let me know and I’ll provide more info…

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