Tag: svg

3D (STL) to 2D (SVG)

Post author By Pete Prodoehl
Post date 2021-01-09

Back in 2015 I used Rhino to convert 3D files into 2D vector files that could be used in illustrations, instructions, etc. You can see what I’m talking about in 2D to 3D to 2D. Sadly, Rhino is not cheap, and I do not have access to it. Instead I would often do fake versions of this technique in OpenSCAD, which you can see in Enclosure Prototyping.

Well, thanks to Trammell Hudson, I can throw all that away! Checkout this post plotter.vision – STL to SVG and then go to plotter.vision and give it a spin.

The code is available on GitHub, and my favorite part is in the README:

I’m not a javascript programmer, so this is probably not very well written.

And yet… It exists, and it works. It may not be perfect, but the great thing about open source is that it can be improved by others in the future.

I’ve included a few results in this posts of things I’ve modeled in OpenSCAD. I think they turned out well and I can see using this tool in the future. Thanks, Trammell!

STL to SVG

Sometimes I need a 2D vector version of something that is a 3D model. Here’s how I do it. First, if there is an STL file, I load that into OpenSCAD.

For this model I wanted a top view so I could use the hole pattern to laser cut a mounting plate.

I select Show Axes because I’m gonna need that later…

The axes will show the center of the canvas, and luckily our model is centered…

Change the view from Perspective to Orthogonal…

If you don’t know the difference between perspective view and orthogonal view, do some research I guess. (I probably learned about them in 7th grade drafting class.) Otherwise, switch between the views and it should make sense…

Okay, next I view the object from the front. Looks good!

I then add the translate command so that I can move the object in 3D space, and I lower it down, in this case 10mm, because the center line is where it will be cut.

The line projection(cut=true) then cuts a slice at the zero point in the Z axis… But we’re not done yet.

(Oh, if you choose cut=false you’ll just get the whole object, not a slice at a specific cross section of it.)

Here we can see what it looks like at an angle, which might make a bit more sense…

Let’s switch from orthogonal back to perspective view… Not required, but I’ll do it anyway.

Back to the top view… and now with the projection you can see the slice we took from the 3D model.

The next step is important… we need to Render the file! You can’t export the SVG file until you render your model.

The model will change… in this case you can see the shapes are now green with red outlines.

And now we can Export as SVG. (You could also use DXF if you need to, though that’s a garbage format I tend to avoid.)

Here’s the SVG open in Inkscape. Brilliant! I can now add to it, and my hole pattern is spaced properly for the mount I want to make. Excellent.

Laser. Cut. Files. (Part IV)

Post author By Pete Prodoehl
Post date 2015-03-30

It’s been a few years since I’ve posted about laser cut files, and by that I mean, the files I prepare to be used for laser cutting, so I thought I’d do an update.

Right now I typically use a few different laser cutters in the Milwaukee area. At Milwaukee Makerspace there’s a 60 watt ULS and 50 watt ULS, but using a Windows PC with CorelDraw for control, and at Brown Dog Gadgets there’s a 90 watt Chinese laser cutter using CorelDraw (and LaserCut 5.3) though it seems to be a much newer version than used at the Makerspace. I also use a 40 watt Epilog Zing at UWM’s DCRL. The Zing uses Rhino instead of CorelDraw, which may sound weird, but it works.

I’ve got a file workflow that can work with all of these machines… which I’ll explain below.

Here’s what my vector art looks like in Inkscape. You’ll notice that the inside lines are blue, and the outside lines are black. This is so we can set a manual cut order for machines that don’t automatically cut inside lines first. (Some software is smart, and always makes inside cuts first, other software… is not.)

I should note that while doing the design work I may end up with multiple layers. Often I’ll use layers to hold pieces or revisions of a design. For our final file though, we want a single layer.

Let’s pretend my design file is named “Panel Mount.svg”, and it has more than one layer. When I’m happy with my work, and have all the things that will be cut on one layer, I’ll save that file, duplicate it, renaming the dupe to “Panel Mount LC.svg” and then open that file. My original design file (Panel Mount.svg) is now safe and sound, but my new file (Panel Mount LC.svg) is about to get altered.

I usually set all the objects to have no fill. This may not be required for all workflows, but I like to be consistent. (Oh, one more thing… you may need to “convert objects to paths” to get things to work like you expect them to in LaserCut 5.3)

For the stroke I’ll set the outside lines to black… (This may be different depending on your laser cutter software.)

And I’ll set the inside lines to blue. Again, this may depend on the laser cutter software & driver you use. Some allow you to set the order of colors, and some may not. If I need more colors I can use red, green, etc. (Also, if you’re working with a laser cutter operator who is colorblind, ask them what colors they prefer.)

If you want to selectively cut things and only have one color, you can use this trick: Load the file into the laser cutter software (CorelDraw, or whatever) and delete the parts you don’t want to cut, then cut. Then “undo” until all parts are back on the screen, then delete other parts, cut again, and repeat. Not the cleanest method, but it totally works. Don’t move any parts, though you may have to ungroup them, and obviously do not move the thing you are cutting.)

Once I’ve applied all the colors, you can select everything and set the stroke. I set it to 0.03mm. This should set it to “hairline” when you import it into CorelDraw. Rhino also seems to do the right thing. If your stroke is too thick it can cause issues. (Always check for the lines to be set to “hairline” after you import your PDF.)

After you change the stroke the lines may appear very faint. If you can barely see them switch the Display Mode to “outline” which makes every stroke appear a black and sort of beefs up the lines.

At this point I run down the checklist…

The file has one layer (If it had more, I duped the file and then adjusted the dupe to have just one layer.)
The file has all objects set to no fill.
The file has all objects set to 0.03mm stroke.
The file has different colors for inside and outside cut lines.

Obviously you can do all the file prep stuff (line colors, stroke, etc.) in your master file, and then dupe that one and delete any extra layers. The order isn’t the most important thing here.

Once we’ve made all the changes, we can save our “LC” version of the file. After that, it’s time to use the File menu’s Save a Copy… command to save it as a PDF file. Note that “Convert texts to paths” is selected. This should create a PDF that does not rely on any fonts being installed. If you used text in your file, this is helpful. It does however mean that you cannot edit any text when you import the PDF into other software, as it will have been converted to lines.

Oh, one more thing! Some older versions of CorelDraw seem to have issues importing PDF files created in Inkscape. On Mac OS X, I just open the PDF that Inkscape created, and export it. It somehow fixes the PDF so CorelDraw likes it. Whatever… it works, so I do it!

(BTW, the piece I used an as example was for the Simple Dual Axis Solar Tracker from Brown Dog Gadgets.)

Tags files, inkscape, lasercutter, pdf, svg

Uncategorized

Snowflakey

Post author By Pete Prodoehl
Post date 2012-11-27

Here’s a thing I’m calling (for lack of a better name) “Snowflakey”. The idea came from the Kimotion Arts store on Shapeways.

Kimotion Arts has these neat 3D printed ornaments with an object arranged in a circle to make a snowflake-like thing. I dig it, so I decided to dig into it.

The first thing I did was fire up Inkscape and draw a really simple figure. It’s terrible, really, but I did it in less time than it took Inkscape to launch on Mac OS X. I created an SVG file, and then exported it as a DXF file, making sure I converted all the line segments into straight lines first. (Of course there were no curves in this drawing, but if there were, I’d convert them!)

Once I had my DXF file, it was easy to pull that into OpenSCAD, and place six of them in a circle with the following code.


objheight = 4;
objcenterspacing = 20;
objrotate = -70;

for (i = [0:5]) {
  rotate(i*360/6, [0,0,1])
    translate([0, objcenterspacing, 0])
      rotate([0, 0, objrotate]) 
        linear_extrude(height = objheight, center = true) 
          import( "figure.dxf" );
}

The code is not the greatest… in fact there is probably much room for improvement, but it’s the first thing I got working, so I ran with it. My idea for the 3 variables at the top were so you could easily tweak them for different art. Sadly, as you change objcenterspacing and objrotate, they affect each other, so it’s a lot of back and forth between those two values. I also could not find a way to assign a filename to a variable, so your DXF will need to be named “figure.dxf” or you’ll need to edit the import line.

Since my drawing was so terrible I wanted to try something else, so what better than Land recreation symbols 27, better known as “Tennis Man” by most people.

A few quick edits and I had this nice Tennis Man Snowflake for that special ball smasher on your list… (Notice the canvas size of 25mm wide by 35mm high. You can do what you want, but the OpenSCAD code will be expecting something close to that. Otherwise you’ll just have to tweak the numbers even more.)

I decided to try once again to draw something. This one took a little longer than a minute, but turned out just as terrible as the first one I did. Still, maybe you like “Blobby Man” as a snowflake.

How about ants? This one is interesting. Maybe spiders would have been a better choice. (And yes, I know I could probably do the entire “6 items rotated” thing right in Inkscape, but that wasn’t the goal here.)

What about the old nag? No, I’m not taking about your mother-in-law (kidding!) but this fine old horse from OpenClipArt.org, where I get many of the SVG files I use. Export this as an STL file and you’re ready to print it on your RepRap!

If you’ve got an improvement to this OpenSCAD code, by all means, let me know. I’m still very much in the learning phase with OpenSCAD, so I do these things to learn, and because of that I’m open to any suggestions.

Tags 3dprinting, art, flake, inkscape, openclipart, openscad, snowflake, svg

Uncategorized

Laser. Cut. Files. (Part III)

Post author By Pete Prodoehl
Post date 2012-04-18

NOTE: See the latest post on this subject: Laser. Cut. Files. (Part IV)

SVG file in Inkscape

After my last post on the subject, Laser. Cut. Files. (Part II), I figured that I had something that worked… but then something came along that worked better!

Thanks to a comment from old pal Thomas Edwards on the Part II post:

Have you tried Inkscape Save as EPS, then Preview EPS to save PDF? (Inkscape Save as PDF might work as well, but I find Corel Draw gets messed up by fonts unless I start as EPS and then go to PDF)

I decided to give PDF files from Inkscape a try. They didn’t work. CorelDraw gets some crazy error trying to open PDF files I create in Inkscape on Mac OS X… but what did work was a two-step process!

Again, my goal is to do all of my design work on Mac OS X, typically using Inkscape, and then moving my files to the Laser Cutter PC running CorelDraw on Windows (yuk!)

PDF file in Preview

So for now, my process is the following:

Create vector art in Inkscape
Save (original) file as an SVG
Save (a copy of the file) as a PDF from Inkscape
Open the PDF from Inkscape in Preview and Save as a PDF
Copy the new PDF file to Laser Cutter PC
Open a new document in CorelDraw and import PDF file

Save as a PDF (again!)

Windows and Linux users, your mileage may vary, and obviously you don’t have Preview.app, but on Mac OS X this process works for me. And as for the note in the comment from Thomas about fonts, I’d be sure to convert any fonts into outlines after I save my SVG file, but before I save my PDF file. (It’s an old print design trick.)

Tags files, inkscape, lasercutter, make, makerspace, pdf, svg