Question about collimated display systems.

[AK Mongo]

Probably used the wrong terminology, but I meant the part you have covered with paper.

[Joe Cygan]

Here's a walk-around video I did a little while ago.

http://www.youtube.com/watch?v=zogFny49zrI

Enjoy!

Great job Gene! Looking forward to future updates.
Joe
g.

Great job Gene! Looking forward to future updates.
Joe

[geneb]

Probably used the wrong terminology, but I meant the part you have covered with paper.

@AK Mongo - The full sized screen will be 180 degrees wide (the test screen is 60 degrees wide). The spaces between the ribs will be filled with foam and then hot-wire cut to shape. It'll then be smoothed out with bondo. At that point we'll either skin it with a high-contrast commercial screen material, or we'll shoot it with the type of Glidden paint that Mike mentions in the display chapter of BRFS.

@Everyone: Thanks for all the kind words! This has been an incredible project - and I'm really looking forward to the next steps. The only sad thing is that I won't be able to use it on the F-15. Collimated displays and bubble canopies don't get along well.

(but it's a GREAT excuse to build Ricardo's Embraer-like cockpit if it'll fit within the screen radius. )

g.

[geneb]

For those that are interested, here's what the rear-projection screen for a 737 FFS looks like:

http://www.diy-cockpits.org/coll/ima...tionscreen.pdf

g.

[yoss]

For those that are interested, here's what the rear-projection screen for a 737 FFS looks like:

http://www.diy-cockpits.org/coll/ima...tionscreen.pdf

g.

Lol , i remeber this item was for sale some two years ago for 500 euro or so...
Of course , local pickup had to be arranged ....

[choffmann]

I must admit I haven´t read this whole thread, and maybe I am a little dim, but what I´m not sure about yet is:
With a 180 degrees screen, how do you set up your projector(s)? You would obviously need more than one, probably three. I ask this with special attention to the focus issues, that Mike pointed out in his tips "depth of field". What I mean is, the projector setup in your system to me seems much more tricky than in a direct beam system, like the one e.g. Ivar Hestnes uses.
Any hints?

Chris

Oh, and BTW: thanks very very very much for your work!

[geneb]

I must admit I haven´t read this whole thread, and maybe I am a little dim, but what I´m not sure about yet is:
With a 180 degrees screen, how do you set up your projector(s)? You would obviously need more than one, probably three. I ask this with special attention to the focus issues, that Mike pointed out in his tips "depth of field". What I mean is, the projector setup in your system to me seems much more tricky than in a direct beam system, like the one e.g. Ivar Hestnes uses.
Any hints?

Chris

Oh, and BTW: thanks very very very much for your work!

Chris, the 180 degree version will indeed use three projectors. There will be some slight focus issues for sure, but I don't anticipate that they'll be that bad. Keep in mind that to get it "perfect", you've got to spend some serious coin on optical correction.

I don't know about Wayne, but I really didn't notice any focus issues at all with the test rig. The extremely low resolution could be a contributing factor as well. The projector being used has a native resolution of 800x600 and it was interpolating an 1024x768 input signal. We'll have to see how it looks when tried with an HD projector, but I don't anticipate any insurmountable issues.

g.

[Matt Olieman]

Regarding three projectors, or may be more? Early versions of the collimated display systems had up to 5 projectors, these were CRT's (three tubes) to keep things in focus and get a higher resolution. The projectors were mounted on the outside of the sim (keep the heat out) and a small portion of the front of the projector was inside the rear display unit. Although the 5 projector sim I flew, when you looked around the edges, the edges were out of focus.

With today's technology, projectors have more of a depth of field ration then earlier models, also the resolution has increased dramatically. Let's not forget about the size of the units. My first projector, NEC 1200D (I think), it took two people to pick it up.

There are Level D's with 180+ degree using 3 projectors today.

Matt Olieman

[wledzian]

I didn't notice any focus issues either, and I was specifically looking for them. In particular, there was a bit of a screen-door effect due to the small gaps between pixels. I expected that if there were significant issues due to a shallow depth of field, there would have been enough blurring to make the screen-door difficult to see at either the edges or middle of the screen. I noticed no such issues, so the defocus was significantly less than a single pixel.

As gene said, we'll most likely be using three projectors. 3 HD projectors would be ideal, but I don't think that is supported by TH2Go or by DirectX (4096-pixel max horizontal resolution - correct me if I'm wrong). Two HD projectors may get the job done, if there's enough depth of field to front-project onto a 100-degree section of the screen.

[geneb]

There are folks using the Digital version of the TH2G running horizontal resolutions higher than that - think three 1900x1200 displays. It may be more effective to just add two more GTX260 video cards to the system - there's certainly enough CPU in there and the power supply is 1KW.

g.