When I was younger I used to love those magic eye posters. Where there is 3d image hidden in a busy repeating pattern.

They make the phenomenon of depth vision seem crumy and unexciting though. This is because they display images that show depth only, with no relevant colour or value information. And it looks as crap as it would do if you looked at a colour image that had no luminosity information (example sunset pictured). It does present the colour phenomenon, but without any help from its friends.

What I find amazing about depth perception is it is so easy to manipulate! In order to actually SEE in 3d, your brain overlays two pictures taken 6.5 centimetres apart (your eyes) and calls any horizontal discrepancies depth. This results in the incomparable sensation of actually experiencing the relative distances of surfaces.

Easy to manipulate? In order to capture all the depth information you can ever know, all you need is two representations of the same thing, from two slightly different positions. This can be captured with a digital camera, or using 3d software, or better yet, using pencil and paper: draw a cube - then, draw it again from a slightly different angle. The brain is then delighted to combine these two images, compute the differences in the shapes and present you with three dimensional understanding.

It will do this provided you do one thing first: Look at one image with one eye, and the other image with your other eye. This requires you to converge your eyes on a different point to the one you're focusing on.


I've forgotten where I was in the flow of things, but anyway. Those magic eye pictures give you only depth by only displaying horizontal shifts to a repeating pattern. The similar repeating pattern is a hook to catch incorrect eye-divergence that will lead to the overlaying of two slightly different images; creating horizontal discrepancies from which alone your brain generates the experience of distance. Yes, it is amazing.

Novel though it may be to hide depth in a load of static, it does not compare to seeing 3d images in colour. If you are not trying to hide the image, then you do not need to encode the depth and do away with the colour. Colour-3d is the most literal means of representation there is (using images) so say I. And again, it is EASY to achieve. If Quake 3 rendered two screens, one for each eye then the game would be every bit as 3d as real life. A whole new tang of reality, and easier too, I imagine - maybe it would distract next-gen game developers from ramping up the texture detail on their shit ideas for a few minutes. Imagine the blockbusters - all that 3d data they have on kingkong which they just pancaked away. The theory is all there, the technology is there, the brain is willing and able - representation of the third dimension is waiting and has been for ages, it is a real low-hanging fruit.

And the only challenge facing it is getting different pictures to each eye in a convenient way. Most well-konwn are the red/blue 3d glasses, and VR goggles (two tiny screens inside some binoculars). Polarised screens and glasses can also be used, so that the left hand side of the screen is hidden from your left eye, and the right side hidden from your right eye to create boss-eyed convergence where each eye is pointed at the opposite half of the screen. Prisms can be cleverly fitted into the glasses, so your line-of-sight converges at the same distance as your focal distance. It is rather crude though.

Also interesting, I think, about seeing in 3d is how much more vivid materials look. Especially reflective or transparent materials where differences between the difference in position of the two eyes are magnified greatly. For example when a highlight on surface can be seen by one eye but not by the other. These sorts of differences result in an image of a reflective material that is much more vivid than what is captured by a one-eyed camera.

In a more coherent reflection, the reflected image is discernible behind the reflecting surface, and focusing 'through' the surface to bring the reflection into convergence provides you with a wonderfully vivid appreciation. The same is true of refraction in plastic or glass or even subtle specular reflections on skin - when there is slight disagreement between the two eyes on the coloration of surface at a certain point, it tells you about the material.

Just as interesting is the potential for using 3d in abstract things, like computer interface for example. At the moment your screen is flat like desk, and flat things accumulate on it on top of one another, with things hidden behind other things. If you added another dimension to it there would be real space between the desktop/wallpaper and the currently active window. Ontop of this they would be a whole lot easier to use.

There are currently many 2d depth cues used to convince you to think about the interface as a 3d space. Drop shadows, occlusion, dimming of background windows and 3d effects everywhere, like bevelled edges, shading and highlights etc, to show relationships. With a 3rd dimension there would literally be space between these overlapping elements and prioritisation would be much more immediate. I dare say there would be room for greater innovation than that if you thought outside the square. But seeing a window floating in space above the desktop is uncanny - I tried it.

One of my favourites below, done with Bryce a few years ago. At the time I used two rolled up tubes of paper, taped together like binoculars. I pointed them at the screen and used them to make sure each eye could only see what it was supposed to, reducing the challenge of deliberately choosing an incorrect vergence. I would love to do more with this idea, but if you do it alot then your auto-focus stops working for a while and you have to frown (manual focus).



Well done on reading that sack of potatoes.