Grrr... Arrrgh! In this tutorial, I'm going to guide you gently through the process of using Autodesk 123D Make to turn a 3D model of a dinosaur into a cardboard model kit. It's extremely simple to do, even if you have no prior experience of using 3D software. You will, however, require either a laser cutter or a heck of a lot of patience for cutting cardboard.

123D Make is free and available to download for Macs at http://www.123dapp.com/make. There are also plans in the works to release an online version of the software which will run on PCs as well as Macs, hopefully within the next few months.

You can now buy a pre-cut version of this kit at the Instructables Store! Woohoo!

Step 1: Start Up 123D Make

First things first: open up 123D Make. You should be presented with a clean, almost empty interface.

In the top left, you'll see a tab labeled "Start shape". This is where you choose the object that you'd like to slice. You can either select a shape from the small library of default models, of you can import your own STL or OBJ file. If you've got something other than a T-Rex that you'd prefer to make, then go ahead and do that.

You can download the T-Rex model here and then open it by clicking on Import in 123D Make.

2304_Tyrannosaurus_Rex_ASCII.stl
Download View in 3D

Step 2: Choose a Construction Technique

If all has gone well, you should now see a dinosaur doing an impressive tail-stand in the 123D window.

123D Make lets you choose how you want to construct your model. Your options are Interlocking Slices or Stacked Slices. For this project, select Stacked Slices.

Step 3: Choose Your Material Dimensions

The dinosaur should now appear as a rather low-resolution stack of thick slices. The blue slices indicate areas that would be structurally flimsy or poorly connected to the rest of the model. We're about to change all the slices around a bit, so don't worry about those just now.

Notice that a new tab has appeared on the right, displaying all of the finished pieces.

In the tab labeled "Cut Sheet Layout", set the print size to match the dimensions of whatever piece of cardboard you're using, as well as the appropriate thickness.

Step 4: Set the Object Size

In the tab labeled "Set Physical Object Size", enter the desired dimensions of your dinosaur. If you change one dimension, all of the other will scale accordingly. The thickness of the slices, however, will remain the same. This means that increasing the total size of your dinosaur wil increase its resolution, making it appear much better defined.

Step 5: Re-orient the Slices

At the moment, the slices are all oriented so that there are many small slices rather than few big slices. In the tab labeled "Slice Control", click on View Controls. This will bring up a set of axes that can be clicked and dragged until the slices are aligned along the length of the dinosaur. Move them around until you're happy with the position of the slices.

Step 6: Familiarize Yourself With the Assembly Instructions

You can click on View Instructions in the "Assembly Instructions" tab to bring up a preview of how the model will fit together. Drag the slider at the bottom back and forth to see how all of the pieces assemble.

Step 7: Output an EPS File

Now you're ready to export your slices as 2D vector images. In the "Output" tab, click on Export.

123D Make will automatically add number and alignment markings to all of your slices, so you don't need to worry about figuring out which piece goes where.

TRex Slices.eps
Download

Step 8: Cut Out All of Your Slices

I highly recommend using a laser cutter to cut all of your pieces from cardboard, but with enough patience you could also make them using a craft knife. And by "enough patience" I mean "the willingness to invest several hours, perhaps days, of precise finger-aching labor".

If you're using a laser cutter, set it to vector cutting mode and adjust the speed and power so that it cuts all the way through the cardboard on the blue lines but only lightly etches into the cardboard on the red lines (i.e. the labels).

Step 9: Sort Your Pieces

Make a pile of all of your slices, ideally in some sort of rough order. Notice that each slice is marked with a number* as well as several small crosses or partial crosses. These crosses are used to precisely align the layers.

*In some cases, where all the pieces within a slice are not connected, the slices will be labeled with multiple numbers. For example, slice 6 might be divided into slices 6-1, 6-2, 6-3, etc.

Step 10: Align and Glue the Pieces

It's time to start building! The best way to align each slice with the one below it is to poke a pair of pins through the little alignment markings, then line them up with the corresponding markings on the previous slice. Once you've got them aligned, glue the slice in place.

In this manner, gradually build up your dinosaur! It's like an archaeological dig in reverse...

Step 11: Keep Building

Now, just rinse and repeat (only without the rinsing - cardboard doesn't like getting wet). Keep adding layer to your model until you have yourself a dinosaur. You may find that some pieces cannot be added until you've attached subsequent layers, i.e. in places where there are overhangs on the model.

How long this takes will depend on the size of your model and the thickness of your material.