From Processing To Painting

I’d been working on using Processing to create these grid patterns using circles of varying diameters for a while now, but moving from the digital world to the physical world is something I first started experimenting with last fall when I was attempting to win a laser cutter. While I love laser cut wood, I wanted to try applying the idea to something different, and it’s been a long time since I put paint on canvas, so…


More info on this series of painting (titled annular) can be found on the project page, but the basic process involves running a Processing sketch, using the output to cut stencils, and then painting using the stencils.

Cutting a Stencil

The Processing sketch outputs a PDF file, which is a vector file easily opened in Inkscape and adjusted to the correct size. I then save out the file as a DXF to load into Silhouette Studio to cut the stencils. (I could use the laser cutter, but the laser cutter is at Milwaukee Makerspace and the Silhouette is in my basement, so it’s more convenient for pieces 12″x12″ or smaller.)


The stencils are cut from old posters that a local printer was discarding. I hate wasting things, and the posters are a great source of strong paper that can be easily cut to size and run through the Silhouette.


I’m pretty happy with how these turned out, and I’ll be creating more of these. Ultimately it would be nice to have 64 of these, but that’ll depend on funding. (And yes, these pieces will be for sale.)


Don’t forget to check out the project page for annular where there’s more info on the concept behind these pieces and plenty more photos.



Cutting with the Silhouette Cameo


I (briefly) mentioned the Silhouette Cameo cutter in a previous post, but I thought I should dedicate a full post to it and how I use it.

I treat the Silhouette Cameo like a CNC machine, and have a similar workflow to the one I use with the laser cutters at Milwaukee Makerspace. I know the Silhouette folks have the Silhouette Online Store where you can buy ready-made shapes to cut, but we’re makers, and we make our own things, so I use Inkscape and if I need a shape I hit up OpenClipArt and find what I need. (Note: All the art on is in the Public Domain, which means you can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission, because permission has already been granted.)

My daughter wanted a kangaroo cut out of vinyl to give to her friend, so I found a kangaroo on OpenClipArt and cut it for her.

Kangaroo in Inkscape

The files on OpenClipArt are in SVG format, which are perfect for Inkscape, as they are the native file format, meaning you can open them right up with no conversion necessary. Here’s our kangaroo in Inkscape. (I won’t go too deep into vector artwork, but if you don’t know, you can scale up and down vector art with no loss of quality, as it’s comprised of lines defined by fancy math, and not a set grid of pixels like raster art, or a digital photo.)

Resizing in Inkscape

The final piece was to be about 4 inches wide, or roughly 100 mm. (You can work in Imperial or Metric measurements in Silhouette Studio—and Inkscape—so use whatever you’re comfortable with.)

I resized the document to 4″ x 3″ using the Document Properties dialog box…

Resizing the Kangaroo in Inkscape

You can see our kangaroo will need to be shrunk to fit within the confines of the document…

Resizing the Kangaroo in Inkscape

Resizing something proportionally in Inkscape is pretty simple. Use the arrow tool, hold down the control key, and move one of the corner points. There’s actually more than one way to resize things, but for eyeballing it, this will work.

Resizing in Inkscape

OK, once we have our artwork the proper size, we can save it (still in SVG format) and the we’ll need to save it as a DXF file so we can get it into Silhouette Studio.

Select ‘Save a Copy…” from the file menu…

Kangaroo in Inkscape

Select “Desktop Cutting Plotter” from the file type menu. (You’ll see it has ‘dxf’ in the name as well, and you may have other DXF options depending on your Inkscape installation, but this one works for me.)

Kangaroo in Inkscape

You shouldn’t need to check either checkbox, just leave the options as they are.

I should note that when exporting DXF files for other purposes, such as loading into OpenSCAD for 3D modeling, we would have needed to convert all the curves to straight lines before creating our DXF file, but the Silhouette Studio software will work just fine without this step.

Kangaroo in Silhouette Studio

OK! We now create a new file in Silhouette Studio, and you can just drag and drop your DXF file onto the canvas. Once it’s there you can resize it as desired. (Wait, didn’t we size it in Inkscape already? Yes we did, that was just my way of teaching you one more thing about Inkscape. You’re welcome!)

Once you’ve got your artwork sized and positioned, you can do your cutting with the appropriate settings.

Kangaroo cut from vinyl

Here’s our final version of a white kangaroo, which my daughter gave to her friend. Hooray for CNC machines that can cut vinyl!

(You may be saying, “Hey! That kangaroo looks larger than the 4″ x 3” one you mentioned above! And yes, it is. After cutting one, a much larger version was requested, so that’s the one you see here.)


The Aluminum Velociraptor

Velociraptor Silhouette

I’m not an expert on dinosaurs, but the velociraptor is one of the more respected of their ilk (so I am told) and you really do have to respect such a clever girl properly, so I grabbed this velociraptor silhouette from OpenClipArt knowing that I’d find a use for it some day…

Save as DXF

Since I can now easily cut things like paper and vinyl (did I mention I picked up a Silhouette Cameo?) I opened the SVG file in Inkscape and exported it as a DXF so I could import it into Silhouette Studio.

Silhouette Studio

Now, typically when I export DXF files from Inkscape for 3D printing or laser cutting I need to first remove all the curves by making them straight lines, like I did for my MAKE piece, but the Silhouette software doesn’t mind the curves.

Velociraptor MacBook

A quick cut of the vinyl and I’ve got a Velociraptor stuck on my aluminum MacBook… but wait, there’s more!

Paper Dinosaur

Since I also had a test cut made with paper, and there was some pink foam in the workshop, and we were planning an aluminum pour at Milwaukee Makerspace the next day, I had this crazy idea to use my drill press as a makeshift mill and cut out a piece of foam in the shape of the velociraptor. (You may remember Kevin’s FEAR that was made in a similar fashion.)

Mill Press

I jammed the base up into the foam so the bit was sticking all the way through so I could just run it and not have to lower it. I was then free to use both hands to move the foam around and cut it. (My jigsaw broke last year, but even if it still worked, I don’t think the cutting area of the blade would have been tall enough to fit the pink foam piece I had.)

Obviously using the CNC Router at Milwaukee Makerspace would have been more precise, but I really didn’t have time to do use it. (This was all pretty last-minute.)

Foam Dino

It worked pretty well! With the first attempt I used too large of a bit, but the second try turned out good. I ended up bringing both of them to the casting.

Velociraptors with sticks

For the aluminum casting you need a box, so we built a box and attached some foam sticks to each piece. We used a glue gun, but you need to be careful not to melt or deform the foam too much. I’ve been told that using the glue gun before it gets too hot, or unplugging it and letting it cool before use might be helpful.

The wider sticks in the center of the body are mean to funnel the molten aluminum down to the piece, while the smaller stick on the tail is meant be a vent.


The next step was packing the pieces in petrobond, which is a casting sand with oil in it. You need to tamp it down and pack it tight. (Somehow I managed to do a pretty good job at this.)

Cast Aluminum

Here’s the pieces fresh out of the box (after cooling of course!) There’s also a tiny bird up in the corner. We had a snake/worm shape as well, but somehow it disappeared in the process. Kevin (who helped me with all of this) then chopped my dinosaurs from the big chunk with a bolt cutter.

The Aluminum Velociraptor

And here’s my (mostly) done Aluminum Velociraptor! I’ve still got some cleanup to do, and then need to decide how to finish it, but that’s another project, and yeah, I’m already planning some pieces for our next pour in a few weeks!

Big thanks to Bret, Matt, Kevin, and everyone else who helped make this happen. It was an awesome event, and pretty amazing to show up with some pink foam and walk away with a cast aluminum piece. (Here’s a short video of the event.)