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From Blender to Ponoko

Posted by Grogyan 
From Blender to Ponoko
August 12, 2009 05:12AM
I'm nearing completion of a design that I would like to get made by Ponoko, and having trouble in getting a reasonable output method whereby I can place a bunch of bits within a Ponoko template.

I'm doing this with free tools, I also use Blender as my preferred modeller.

I've found that that the DXF exporter isn't reliable enough to produce a suitable cutting path for laser cutting, leaving the only method left.

Would anyone know of a reliable method to produce an SVG file from an STL/OBJ file?

Vik suggested that using the slicer in MeshLab might work, but found it makes it worse, and not produce anything.

Any ideas?
Re: From Blender to Ponoko
August 12, 2009 05:32AM
Freesteel slice looks like it will do what you want on Windows [www.freesteel.co.uk]

Re: From Blender to Ponoko
August 13, 2009 03:15PM
I tried several attempts, and I find its not working either.
Then I found out that Carve in Skeinforge should also work, but I don't know if its a bug or what, it says its written the svg file, even though it hasn't.

I have both python 2.5.2 and 2.6.2
Re: From Blender to Ponoko
August 15, 2009 03:44AM
slice -z 1 Bed-corner-1.1.stl -o output.svg

Works fine for me and produces the attached svg file.

open | download - output.svg (5.4 KB)
Re: From Blender to Ponoko
August 15, 2009 10:24PM
The file seems to be empty, when opened in InkScape.

When opened in GIMP the edges are not sharp

Carve does work a lot better

But it doesn't like this mesh
open | download - MyZ_3.stl (43.7 KB)
Re: From Blender to Ponoko
August 16, 2009 04:06AM
I viewed the svg in Firefox and it looks fine, but it is filled polygons rather than lines. I am not sure what inkscape needs. It is just xml though, so you can edit it.

AOL says the mesh is non manifold:


validate: number of faces (893) is not even
validate: number of edges (1345) is not a multiple of 3
validate: number of faces (893) is not 2/3 the number of edges (1345)
validate: calculated holes (using Euler's) = 7

It offers to fix it but that always gives an array out of bonds exception on my machine.

Re: From Blender to Ponoko
August 16, 2009 05:59AM
I think FreeSteel is actually converting it to an image format, least that is what I have observed today, because when I open it with GIMP, GIMP says there is do dimensional data in file
Re: From Blender to Ponoko
August 16, 2009 09:07AM
It can do images, but SVG is Scalable Vector Graphics. It is just an XML file with some polygons in it, described as a list of points and with stroke and fill colours specified. Have a look at the .svg file in a text editor.

Re: From Blender to Ponoko
August 17, 2009 12:34AM
I did, weird that it is blank in InkScape. The way ts acting i'll use something that we know works, so far that tool has been Skeinforge Carve.

Did some other playing around late last night, and I got Skeinforge Carve to do its thing properly on the mesh, Blender had mucked it up somehow, so I downloaded a more recent version from [www.graphicall.org], and exported the mesh to stl, and it sliced properly.
Re: From Blender to Ponoko
August 17, 2009 03:56AM
Carve will subtract half the filament width. Does it work with that set to 0?

Did you manage to get a single slice?

Re: From Blender to Ponoko
August 17, 2009 03:59PM
That gives a divide by zero error.
Using an extrude width thickness ratio of 0.1 gives a line width of about 0.5mm, same as the tolerance for Ponoko
Re: From Blender to Ponoko
August 18, 2009 09:10PM

With the current version of skeinforge, carve just carves the shape, it does not inset it. So you can use a reasonable value for the extrusion width, you don't have to try getting it close to zero. Carve just uses the extrusion width to determine the import radius when spanning gaps of a model with holes. If the model is correct, extrusion width will not be used at all by carve.

Preface then turns the svg into gcode and inset then insets the shape by the extrusion perimeter width.

Re: From Blender to Ponoko
August 23, 2009 04:21AM
Thanks Enrique, I noticed that changing the extrusion width didn't change much, just as you said it would.

I did find that if I do try and use the layer thickness to be the whole thickness of the part, more often then not, Skeinforge would muck it up, but if I make the layer, say 2mm, it would work perfectly
Re: From Blender to Ponoko
August 24, 2009 12:16PM
Hi there

I am behind the freesteel slicing tool and I am delighted that people are using it.

I have no idea what you guys are doing, but I am happy to offer my help here.

To Grogyan: The output is not a converted image, it is actual vector data, obtained from slicing the STL file. I have never tried opening an SVG in Gimp, but that the edges are not sharp sounds to me more like Gimp's rendering is not sharp.

Let me know what you need?

-Would you like to be able to specify the colors for polygon and fill?

-Would you like another type of output? Sbdy mentioned G-Code?

-If you can't email, post a message on our blog: www.freesteel.co.uk/wpblog

Re: From Blender to Ponoko
August 25, 2009 05:02PM
I tried FreeSteel again and it still does not open with InkScape, the document is empty.
When I open the same svg file in FireFox a picture is shown, though all the edges are smooth and sharp corners are rounded.
Skeinforge outputs the same design properly
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