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Sunday, December 28, 2008


Hand Drawn Anaglyphs!

You may be familiar with red/(cyan or blue) anaglyphs. These are pictures where a 3D effect is produced by overlapping red and cyan (or blue) images. I have used anaglyphs to make stereo images of Mars and the Sun, for example.

A couple of days ago MiddleOne asked if you could draw 3D pictures. I thought it was possible from my experience with anaglyphs, and we experimented with various coloured textas, but with only minor successs.

Around 5:30 this morning SmallestOne kicked me out of bed, and I started thinking (or maybe I was already dreaming) about anaglyphs. I couldn't go back to sleep, so I tried experimenting. First you need the right colour textas. Our stereo glasses have red for the left eye, and cyan for the right eye. You need a red colour that will be invisible through the left eye, and dark through the right eye, and a blue/green that is invisible through the right eye and dark in the left eye.

It was pretty easy to find a light red text that fitted the bill (our previous attempts had used too dark a red). Finding a blue-green that worked was much harder, and I had to settle for a pale green/blue that sort of worked.

Once you have your colours, then how do you match them up to give depth? I started with simple squares. Blue-green lines to the left of the red lines make the boxes appeare below the picture plane, blue-green to the right makes the boxes appear above the picture plane. The wider the lines apart, the greater the feeling of depth. by grading the line spacing, you can give a feeling of volume to the surface.

You also have to choose your viewing postion, straight up and down at about a meter away works best.

The planet with craters and rings above is the result. Viewing with red/cyan glasses about a meter away gives a nice 3D effect for the cratered body of the planet. The rings are a little wobbly though, but still, this was a hand drawn image using only red and blue-green textas. A little practise (and a better shade of blue-green), and you can draw stunning 3D images without fancy computer graphics programs.

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This looks like a lot of fun Ian. We won't be seeing any stars tonight. It's grey and pouring with rain. You have a middle one and small one. I have minion number 2 and 3 to wake me up at some horrible hour of the morning. We have some three d glasses here too. Out with the tracing paper.
What a fascinating activity! The idea of making your own 3D drawings is a fantastic way of engaging kids with how it works!

We had a lot of fun exploring the huge format, anaglyph images at JPL in California. One of my former students has a great website with 3D photography. I must try to nail down a 3D glasses supplier or try to make my own.

Thanks for trying it out and sharing this. :-)
G'Day MBF, sorry about the weather, at least the anaglyphs give you something to do.

Plakboek, the JPL website is facinating with all the anaglyphs they have there. You can even make your own from the raw images. See this HiRISE in 3D post for some true awesomeness.

I liked the 3D bike on you website, and I will have to play around with hand drawn anaglyphs some more. Just have to find the right blue pen.
Oh, wow. I only just saw this old post of yours Ian. I make hand drawn anaglyphs with my daughter sometimes. Nothing quite to sophisticated as a planet with rings, perhaps, but we've made some fun drawings all the same.
What shade of pencil crayons do you use?
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