## Introduction: 3D to Go

Who needs 3D printers when you can make this kind of thing without one?

The key ingredients? 123DMake and a source for a whole lot of salad deli containers.

There's a similar activity out there that inspired this one, using topographic maps to create 3D models: http://online.wr.usgs.gov/outreach/topo_instructi...

Total time to make this? A few hours, depending on how much fussing you need to do on 123DMake and how detailed you want your ghostly object to be.

## Step 1: A Little Background

At the Exploratorium we've got a new exhibit that fellow Exhibit Developer, Maz Kattuah, and I made as a part of an Exploratorium- Autodesk partnership. It's called How You Slice It.

The idea was to give visitors a sense of how 3D objects are really just a stack of 2D lines- which is how a 3D printers operate, laying down layer by layer of material until you get a Thing.

You can see the exhibit at the Exploratorium or you can find it's twin sister in Autodesk's Market Street Gallery. This Instructable is derived from that very exhibit.

## Step 2: What You Need

Here's what I used.

• salad to-go containers. Alright, I confess that I didn't plunder my recycling as one might. I bought a whole box of these from Smart and Final which was good because I just don't eat that much to-go food. How many do you need? That depends on what you're making. The taller your object is, the more containers you need. Also, the taller it is, the less visible the object becomes- so I wouldn't do anything that is more than about 7 inches total (that adds up to less than 15 double sided containers). What's important is that you get containers that are double sided. You see how the stack of them in this photo are all nested together? You don't actually want that to happen. When you get a double sided container, the two sides are slightly different so that when you cut the two sides apart and stack them up, they have a slight offset. More on that later.
• scissors
• a sharpie
• printout plans from 123D Make

Not seen here, but you will also need:

• a couple of thumbtacks

• a printer

## Step 3: Getting Started: 123DMake

Please note! I'm proceeding with the assumption that you've
already downloaded this free software and have some familiarity with it. There are lots of tutorials out there for how to use this program and this is not one of them.

First off: Pick a 3D model that you like- but make sure that it will fit on your stacked salad containers! The containers I used have a flat surface of 5"x6." Forget about making a life size cat unless you've got a hot tip on some industrial sized to-go containers. Also consider how tall your object needs to be. The taller it is, the more salad containers you'll blow through. The ghostly hand I made used up 13 containers.

So...assuming you've got an object uploaded that you're ready to slice, here's what you do:

• Get your settings right: make your own custom Manufacturing Settings, using the tool bar at the top left. I've named the settings for this project Salad Box Stack.
• Set the offset to .25.
• You'll be printing the contour lines onto paper; make sure to give yourself lots of margin room by really shrinking the height and width settings. As you can see, I set my height and width to 7" for 8.5" x 11" paper- this was the only way I was able to get prints that didn't cut off the contour lines. It's finicky and annoying- plan on having extra paper on hand for trials.

## Step 4: Prepare Your Containers

• cut them in half
• depending on what your containers are like, stack them so there's an offset between the two halves. That might mean rotating the two halves, alternating between top and bottom, etc.

## Step 5: Lots of Cutting

It's craft time!

• cut all those little contour lines out
• put them in numerical order, in neat little piles

## Step 6: Layer by Layer

OK- you are now the 3D printer.

• pick a good spot on your container to start. I took a good look at my model and took a stab at placing its start point. Try to anticipate how much room the features will need as you stack things up.
• outline the contour line on the first container.
• and mark the two registration dots with the sharpie
• find a discrete spot to add a number! You'll be so thankful to have these containers numbered when your cat knocks them over

## Step 7: Off and Running

• grab the next container and put it under the first one
• using the thumbtacks, push through the registration dots so that you poke the layer beneath

## Step 8: Keep on Keeping On

• remove the previous container so you just have the one with the poked registration marks
• grab the next contour line cut out
• add some tape to the back of it so that you can tape it face up onto the new container
• using the poked registration dots, match them up to your contour line
• trace the contour line, mark the registration dots...

## Step 9: Wax On, Wax Off

...and you'll be doing this for awhile.

Remember that each contour line will have it's own set of registration points, so some layers will keep you busier than others.

## Step 10: Yay! You're All Done!

You may find that the murky ghostliness of your stacked containers is a little too murky. If this is the case, I recommend back lighting it, with a light box or, even better, the big light box in the sky. These containers can look great as little spooky windows.