How to Build a Wiremap

Step 7 Ray Tracing

In this step, we'll make a straight edge between the projector's focal point and the mapline.

Glue two pieces of foam core together. When gluing them together, try to stay within an inch or two the outside edges (so that when you pierce holes into your foam core, you won't have to struggle through the glue).. Then tape this to the third piece of foam core. Then - tape it all to the floor:

core . . . . . .===============
. . . . . . . . . . . . . . .taped to
core . . . . . .===============
. . . . . . . . . . . . . . .glued to
core . . . . . .===============
. . . . . . . . . . . . . . .taped to
floor _._._._._._._._._._._._._._._._._

Now, measure out where your projector should roughly go (centered on the depth line and as far from the mapline as your depth is). Tape a piece of plywood at that spot.

Draw the depth line onto your plywood. A good way to get the straight edge here is to tape a piece of string to the center of the mapline and pull it taught. When it matches the depthline on the foam core, mark up your plywood and draw it out.

Then, measure from your mapline to draw the intersect - where your projector sits.

Take some thread and tie it off on a hex nut. Drill a screw (or nail a hammer) through the hex nut into the intersection on the plywood.

Now you have a straight edge long enough to follow your path of light!