Dancing mirror light boxes

[mattbell]

After going way hard-core the last couple of years, I'm taking it easy for this year's burning man.  Thus I'm only doing a moderate-sized art project.  A friend of mine asked me to create some interesting lighting for a dance/chill/meditation space complex she's designing. 

I came up with the idea of creating a lamp that is surrounded by inward-facing mirrors so that light must bounce one or more times before exiting the box of mirrors.  By appropriately shaping the exit holes, I can get multitudes of interesting patterns.  The resulting light cast out seems to be equal parts geometry, fractal patterns, and randomness. 

I found that building physical prototypes was expensive and time-consuming, so I turned to 3D modeling software to do the trick.  I found that no package I tried, even expensive commercial software like Lightwave, would bounce light sources off of mirrors.  They would raytrace from the camera, bouncing off any number of mirrors, but wouldn't raytrace light from the light source.  Even radiosity algorithms failed to do this.  It seems that the real world is so relentlessly complex that 3D modelers need to take severe shortcuts in actually figuring out what any real scene should look like.  Come to think of it, I haven't seen any light sources casting light bouncing off a mirror in any Pixar movies...

In the end the 3D modeling software Blender was somewhat useful in that i could at least model the pattern of light I'd get from a given exit hole by placing the camera at the position of that hole and replacing the light source with a ball with emissivity set to a particular value.  As a result, I was able to try out a very large number of different shapes for the mirror box, and save a lot of time and money.  Generally speaking, Blender is very full featured, and I was able to do some good basic things with just a couple of hours of learning.

One of the constraints of the project was that the light pattern should have fivefold symmetry.  This limited my choice of shapes.  I settled on something akin to a five-sided pyramid with a truncated top, attached to an inverted mirror of itself at the bottom.

Here's what it looks like in the light:


On the inside:


And here's the light pattern it casts with various choices of exit hole:


These pictures are okay, but imagine that each little pattern copy moves in a different direction when you move the lightbulb.  The results are hypnotic ... each pattern encircles the others in a luminous pentagonal square-dance. 


Note that this is a 1/3 scale version with a very dim lamp.  The real version is supposed to light up a 60ft dome, so I'll need a much brighter lamp, like this 750W monster:   (This is me comparing its brightness against the brightness of the projectors it will be competing with.)

 

Comments

[savorie.livejournal.com]

Really? It worked on my Mac/Firefox combo.