Introduction: 10 Minute Mini 3D Projection

If you have ever been to a trade fair that was bigger than your backyard, you may have seen some magic 3D projections floating in space, wondering how on earth this might be possible and why it is so dark there.

I saw this in many variations, on the International Automobile Exhibition as a mapping on cars or on Gamescom in smaller boxes om game consoles. Theme parks use these in ghost trains. These smaller boxes are for example offered by I googled the magic behind these boxes and it was ridiculously easy.
So wonder no more, I will show you how to make a mini-3D-projection for less than a dollar (unless you have no smartphone, then it will be about 181 dollar) using exactly the same technique.
I know, this looks photoshopped, but trust me, it's not.

Step 1: How Does It Work?

Do you really want to know? Some things should remain magical. But as you may find out while crafting, anyway, I will tell you how this works:

This technique is called Magic Screen. The iPhone projects the image of 2 wheels, the yellow stripes, the driver and the light onto a 45° overhead transparency. You can’t see that because as the name says, it’s transparent. But you can guess where it is on the picture, it makes a tiny brightness difference when you look on the left side of the inner wall.
The transparency sheet mirrors it onto a virtual layer that is at the same height as the car. But only the light areas are mirrored, the dark areas aren’t reflected. So the illusion is created, that these magical object float in the air.

Nevermind the bumpy camera panning, it should just show that the layer is really in 3D space and works from every perspective.

Step 2: You Need:

  • A smartphone or iPod touch or anything with a small, but not too small display and internet.
  • Overhead transparency sheet or anything that resembles it, like a transparent package from an SD-card.
  • Thick paper: about 160 g/m2, or just two normal sheets glued together.
  • A printer
  • Crafting stuff: scissors, glue, ...

Step 3: The Cave

By the way, I made a video how I glue the whole thing together. So if you are not sure about anything, you can look it up there.

Before you can start, you have to print page 2 and 3 from the PDF.
Let’s begin with the cave. In general, before you glue anything together, you should scratch all folding lines with a cutter or your scissors. That guarantees nice folds. You can’t see that in the video because it is hell boring. I made it before I cut it out, and you should do so, too.
The cave consists of two parts, the background with the ceiling and the floor. It is folded inside out, meaning the printed background is on the inside. Glue one flap at a time and don’t attach the two front parts yet. You need to put the transparency through this space later.
I use little pins to help the glue dry on the right place.

Step 4: The Car

The car is an Opel Adam, by the way. It is cool and cute and had the right size.

It should be quite self-explaining. Dotted lines are valley folds, dashed lines are mountain folds. I used a round pen to roll the sides up a bit, giving it the right shape (It is a bit narrower on top, just like any other car).

Step 5: The Transparency

You can’t see that in the picture, but trust me, I am fixing a transparency sheet on the paper with tape. Two thirds of the the involved parts are invisible, making it kind of hard to show it on a photo.

The transparency should be a bit bigger than the shape, then cut along the black lines and you have a perfectly shaped transparent foil.

Step 6: The Marriage

Time to bring all three parts together. Already over 10 minutes? Well, that was more like a approximation.
  • Glue the car in the cave. The flap goes to the white area on the floor. Something flat, like a tweezer, helps to fix the flap under the car. If the car nearly touches the wall, it is on the right place. Let it dry a bit.
  • Glue the transparency on the flap. I outlined it pink, so you can see where it is. Put glue on the flap on top, not on the transparency. When you fold the flaps on front of the cave outwards, you can put it in easily. Let it dry.
  • Attach the 2 remaining flaps. Fold them back and glue them to their respective flaps. Again, I used pins to hold everything in place.

Step 7: The Magic

On the instruction sheet, you can find a QR-code that links to the animated mini-film. Open it on your smartphone, then zoom and pan it in full screen mode to the right size and place.

Switch the lights off and place your device upside down on top of the papercraft  -- The projection is mapped right onto the car!

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