How to Build a Wiremap

Step 4 How Many Wires?

The number of wires you choose to have in your wiremap will effect you in two ways. With less wires, you'll have an easier time constructing and calibrating your project. With more wires, you'll have to be more precise during construction and calibration, but the end result will have a higher resolution.

If you're looking to learn about the project, 64 wires should be fine. You'll get a good idea as to how things work, and you'll still get a pretty cool effect with a few of the programs. If you're looking for something more challenging, try 96 or so wires. And if you're into intricate work and are willing to spend a bit of time on this project, try 128.

In any case, once you figure out what you want, write down the following on your xl sheet:

64 wires
Available to projectors w/ a horizontal res of 1024, 1152, 1280, or 1920
Mapline Length: 32"
Map Unit: 1/2"
Depth Unit: 1/2"
Depth Levels: 40

80 wires
Available to projectors w/ a horizontal res of 800, 1280, or 1920
Mapline Length: 35"
Map Unit: 7 / 16"
Depth Unit: 7 / 16"
Depth Levels: 45

96 wires
Available to projectors w/ a horizontal res of 1152, or 1920
Mapline Length: 30"
Map Unit: 5 / 16"
Depth Unit: 5 / 16"
Depth Levels: 64

100 wires
Available only if your projector's horizontal res is 800
Mapline Length: 31.25"
Map Unit: 5 / 16"
Depth Unit: 5 / 16"
Depth Levels: 64

128 wires
Available to projectors w/ a horizontal res of 1024, 1152, 1280, or 1920
Mapline Length: 32"
Map Unit: 1/4"
Depth Unit: 1/4"
Depth Levels: 80

How many nuts and bolts do you need? Just take your number of wires and double it!

In case you were wondering what these values are: The mapline length is the width of your projection at a given distance. Remember how I explained this in the beginning with the vertical strips? The number of wires is the number of vertical strips, and the map unit is the distance between each vertical strip.

Determining the Depth

Here are the two guidelines for figuring out how close your wire field is to your projector.

1 - Throw Ratios Notice in the image below: you've got a depthline and a mapline. The length of these lines are the same measurements you used to determine your minimum and maximum throw ratios. The ratio for your plan must fall within your projector's throw ratio.

2 - Closest zoom The center of your wire field must be further than your closest zoom measurement.

So, given that your mapline is a fixed width, find a depth that works for both your throw ratio and your focal distance.

Example please!

So, for my construction, I went with 128. My mapline length is 32".

My widest ratio is 1:2. With a fixed mapline of 32", the depth for this throw ratio would be:

depth = x
1:2 = 32": x corresponding ratios
1 * x = 32" * 2 cross mutiply
x = 64"

My tightest ratio is 27:72.

depth = z
27 : 72 = 32" : z corresponding ratios
27 * z = 32" * 72 cross multiply
z = (72 * 32") / 27 divide
z = 85.333

To fit my projector's throw ratio, my depth must be between 64" and 85"

Closest zoom

My projector's closest zoom distance is 45". The center of the wire field must be greater than 45" away from my projector. Because the wire field is 20" deep (as is everybody's), the center of the wire field is 10" shorter than the depth. So, as long as my map line is greater than 55" out (45" + 10"), then I'll be okay.

For my case, I can just disregard this because my throw ratios are more limiting than that anyhow.

I ended up settling on a 68" depth from my projector to the mapline. This gives me a 4 inch margin of error (I'd always give myself at least a 2" margin of error, just for good measure).