Introduction: Giant Laser Cut Bulbasaur
In this Instructable I'll show you how we've built a giant Bulbasaur consisting out of 216 laser cut plywood pieces and over 600 zip ties!
Step 1: Downloading the 3D Model
First of all we'll download the Bulbasaur model from Thingiverse. It's made by Flowalistik, he has a bunch of very nice low-polygon 3D-models of different Pokémon. I went with the Bulbasaur because it's one of my personal favorites and I think it's the most recognizable model of the low polygon Pokémon.
You can find the Bulbasaur 3D model here: http://www.thingiverse.com/thing:327753
And all Flowalistik's models here: http://www.thingiverse.com/FLOWALISTIK/designs/page:1
Step 2: Converting the 3D Model to 2D Pieces
Once you've downloaded the model you can open it up in Autodesk's 123D Make. This is a free piece of software that allows you to convert 3D objects into 2D objects. Which is exactly what we need if we want to laser cut them.
(As of the 31th of March Autodesk has closed down the entire 123D app family. 123D Make is now integrated as an app for Fusion 360 called: Slicer)
- Setting up the manufacturing settings
First of all were going to add a new material that has the correct dimensions of the wooden sheets that we are going to use as stock material. I went with 1200x800x6mm (31x47x1/4") poplar plywood. This will provide enough strength when everything will be put together while being cheaper than easier to laser cut than birch for example.
- Scale the object
Secondly, we're going to have to scale the 3D object. We are going to make a huge Bulbasaur, but we can't make it too big. Because otherwise it won't be able to get out of the door of our shop anymore. I chose a width and height of about 170cm (5'7") which results in a length of 207cm (6'9") after scaling the model uniformly.
- Construction technique
Next up we have to select the construction technique we want to use. In this case it's "folded panels". This will convert every flat face of our 3D object into one single panel which we can laser cut later on and attach back together in order to construct our giant Bulbasaur.
- Manually add/remove seams
Since this is a construction technique that is mainly used for papercraft it won't only generate the seams we need in order to cut the panels but it will also generate folding lines. Which we don't want in this case because we will be laser cutting it out of solid wood so we won't be able to bend it afterwards. That's why we have to select every line where we want to split the faces manually.
- Joint type
Select the joint type "Laced". This will automatically generate a series of holes with a chosen diameter along the edges of our seams. We can use these to lace the pieces back together with zip-ties afterwards.
After we've selected all the splitting lines, there are still some errors we need to address. 123D Make seems to have a little problem when there are holes inside of a panel so for example with the opening for the eyes, it automatically splits the panel into two different pieces, that don't have a hole inside itself. But this isn't really too big of a problem because we can still change those lines afterwards when we get the 2D drawings. Also some of the panels are showing up red which indicates that there is an issue with them. This just has to do with some of the pieces being too small to fit all the connecting holes inside of them. Which again isn't that big of a problem because we can fix all this in the next step.
- Export as PDF
When everything is setup correctly I can export all my drawings as a PDF. This PDF contains all the 216 pieces that we will need and it scatters them, in this case, over 26 pages. Each page represents one sheet of 800x1200x6mm (31x47x1/4") plywood we will need for laser cutting all the pieces.
Step 3: Setting the Drawings Up for Laser Cutting
123D Make does a pretty bad job at nesting all these 216 pieces. So I suggest rearranging them manually so we can get away with a few less sheets of plywood. I've used Inkscape for this. Inkscape is a free and open-source vector editing program, comparable to Adobe's Illustrator. It allows you to rearrange some of the parts in order to make them fit together properly and also to adjust the location of the holes in the parts that were showing up as errors. In the end I managed to squeeze all the pieces into 17 sheets instead of 26. So now we can finally start laser cutting. There are two different colors used in the design file. The laser will cut all the blue lines while all the red numbers will be engraved. Each piece has its own unique number so you still know how to connect your pieces. All in all it took me around six hours to cut all the pieces on a 150 watt laser cutter.
Step 4: Assembly
Last part is connecting all these pieces back together. This was done using a bunch of zip ties. I guess there were somewhere between five and six hundred of them in the entire design. For the most part I could rely on the numbers on the pieces in order to connect them together. There was however an error in the automatically generated numbers on the pieces (the numbers near the edges of the pieces are all off by 1, so be aware of that when you use the PDF provided above) Luckily we also had a bit of extra help with a 3D-printed model that we could use for reference. Checking out the model in the 123D Make software also made it a little easier to find out which piece went where and in which orientation. It took us about six hours to put all the pieces together.
Step 5: End Result
We built this giant Bulbasaur as a showcase for our pop-up FabLab in Aalst, Belgium (FabLab Factory) so that's where you'll be able to find it. All in all i'm very happy with the end result because I think it looks really cool. And I don't seem to be the only one thinking that because it proves to be a real head turner.