Well I’ve built 2 - and the better of the 2 is actually a dual lcd projector setup… This is much much easier to do with projectors that have manual lens shift adjustments. Try to avoid using digital keystone! My better setup is using 2 nec np2150’s - 4200 lumen 3lcd projectors. I built a steel rack that stacks the two projectors closely on top of each other both platforms being perfectly level with each other. I’ve found that placement is key and simplifies things significantly. You want the zoom to be either all the way in or all the way out. It’s difficult to align when you are constantly fine tuning the zoom on both units. Keep the horizontal lens shift centered, and I center the bottom of the units vertical lens shift. I then project a grid of 1px thick white lines and adjust the vertical lens shift of the top projector until they are aligned. Voila. Place your polarized filters in front of the lenses (these clip on to my steel rack).

Key things to remember when doing this… 

1) Go as bright as you can! The polarized lenses in front of the projector cut the amount of light projected significantly. The glasses cut this even further. I believe the glasses cut the light by about 40% and the lens by about 30%. This means from each projector only about 1260 lumens actually reach each eye = *2 = 2520 lumens seen. So you can see there is significant lumen loss in the process. My math might be wrong in this, personally it still seems a bit brighter than that with my setup.

2) Very important! You need a screen that maintains the polarization! This can be expensive! I would research this as this is going to be your biggest limitation in making the unit portable. Normal screens will not hold the polarization and the 3d just simply won’t work. I used this on drywall boards that are assembled each time. Pain in the ass. (http://www.goosystemsglobal.com/index2237e.html)

3) Use quality polarized lenses in front of your projector. They will be directly exposed to heat and poor quality ones could warp and destroy the image and alignment. I use these, they were cheap and seem to do the trickhttp://www.3dstereo.com/viewmaster/pj-pfilt-3x3.html

4) Linear polarization is easier and cheaper than circular from what I’ve read so that’s the route I went. The side effect is tilting your head and you may get some bleed from the wrong projector into the wrong eye.

5) Content. Not a ton of content out there - make your own!!

This was a fun build, but honestly I’ve only used it a handful of times. It’s a pain in the ass to setup and build the screens each time. It’s a trial and error type thing too - you have to experiment to see what works for you.

Have fun!
Vj NeXus