Huge Screen Quad-Projector Build!!!

[ZMaverick]

Hey all,

First-time poster here.
I've recently completed a big-screen build, and want to see what y'all think about my setup.

My flight simulator setup consists of a large (10 ft tall!) 180-degree cylindrical screen. I'm using four BenQ W1080ST projectors (mounted in portrait), driven from a single Nvidia Quadro K5000 graphics card (utilizing Nvidia Mosaic to make single 'monitor' from a 4x1 projector array). My computer is a custom built Windows 7 machine, with lots of RAM, an SSD hard drive, and an Intel Core i7 processor. Warping/blending is done with Immersive Display Pro. X-Plane 10 is the image generator, utilizing Fly Elise-ng's Multiview plugin to create four virtual views and render the 180-deg view.

Framerate with the Multiview plugin on is limited. I get about 25 FPS with low rendering settings. Performance monitoring tools show me that the CPU is my bottleneck, likely due to the fact that X-Plane is single threaded (they claim to use multiple cores but that's just for loading the scene, the flight engine only utilizes one core). Any suggestions for ways to improve frame rate in X-Plane 10 (with the Multiview plugin on) ??

Pictures attached!

-ZMaverick

[ZMaverick]

Now with pictures!

[rhysb]

Wesley,

Your on a losing path if you want to render all that on one machine! I'm surprised with what your saying though as my CPU handles xp10 fine it's the graphics card that suffers.

What spec graphics card are you using and when the sim is running what is your CPU load readout?

Rhys b

[ZMaverick]

The graphics card is a 4GB Nvidia Quadro K5000. The GPU runs at about 35-50% load with low rendering settings and hits 95-100% with medium-high rendering settings.

The CPU, on the other hand, is railed at 100%, pretty much regardless of rendering settings (which is actually about 10% total CPU, but 100% on the core that the X-Plane thread runs on). The framerate drops with extra objects added to the scene (e.g. more trees/roads). It appears that the CPU is taxed by the scenery, and there is a lot of field-of-view available in my setup for lots of objects, which loads the CPU to the limit.

[HarryZ]

Wesley,

Curious as to why you used 4 projectors as opposed to 3 for your visuals?   That additional projector is taxing your system to provide the additional display. 

As well I see from the pics that your image blending isn't what it should be with the dark area in the middle of the screen. Blending software should be able to remove that.

[ZMaverick]

Harry,

The primary reason was to for field of view (also was the reason for large screen), which was a higher priority for my application than was raw performance. The four projector setup I used (see picture above) has a 'clear' area in the center that doesn't shadow the screen in which I was able to put my chair/cockpit (which is now mounted on a platform a few feet higher in the air). Alternatively rear projection could have worked, but my floorplan space was limited, so I felt that this was the best all-around option given all of my goals and constraints.
I feel like I've learned alot more in the process of actually building this simulator (acquiring/assembling/configuring the components) that I wasn't able to find out just through research ahead of time.... and hence if I had to start this project over again, I might do things differently (e.g. a different projector setup).

-Wesley

[HarryZ]

Wesley,

Only saw your response today as I've been away. 

The reason I asked about the 4 projectors is that I've installed a 220° FOV visual system using 3 1080 HD ST projectors and the Nvidia 780 GPU.  (FDS 777 cockpit used by CNN on the MH 370 coverage)  While it uses FS X, they get a constant 30 FPS with no stuttering (heavy settings in scenery) I'm assuming that with X-Plane, that 4th projector is really using up the CPU's power and not giving you much more in the way of graphics.

[HarryZ]

Wesley,

Just noticed when looking closely at the pics you provided why you had to use 4 projectors in 2 rows....you could not have obtained an image vertically high enough with a HD ST projector in a single row.   I guess there is a price to pay for that size an image.  A computer having to provide graphics to that size of screen and 4 proj certainly has to be very powerful. Don't have an answer as to how to improve your frame rate.

[Nat Crea]

Four HD projectors...one poor computer can only do so much really?   

Only realistic solution I see is Multi-Channel... ie more computers.


Nat

[ZMaverick]

Harry, By "2 rows" do you mean a 2x2 projector setup? I could have covered the screen with a 2x2 or 4x1 projector setup, however the 2x2 setup didn't allow enough space for my cockpit without shadowing the image.

Over the past few weeks I've been optimizing my system's settings (graphics, bios, X-Plane, etc.) which has given me a few extra frames/sec. If I avoid flying in big cities with very dense object scenery it helps as well, and allows me to get over 30FPS consistently now, with decent rendering settings, which is completely fly-able.

[HarryZ]

Harry, By "2 rows" do you mean a 2x2 projector setup? I could have covered the screen with a 2x2 or 4x1 projector setup, however the 2x2 setup didn't allow enough space for my cockpit without shadowing the image.

Over the past few weeks I've been optimizing my system's settings (graphics, bios, X-Plane, etc.) which has given me a few extra frames/sec. If I avoid flying in big cities with very dense object scenery it helps as well, and allows me to get over 30FPS consistently now, with decent rendering settings, which is completely fly-able.

Wesley,

Yes, I'm presuming (dangerous word!) that to fill your size of screen with a vertical image, you would require a double row of projectors (2 on top, 2 below).  Depending on the throw of your projectors, a single unit would not be able to provide that tall an image.  But you stated that you were able to experiment with a 4 x 1 configuration. If that single row was able to fill the entire screen vertically, then the throw ratio would have been very large.  Most simmers don't have that kind of screen size (vertically) because it usually ends up in some kind of shadow casting which defeats the purpose of a realistic looking image.

But as you are discovering, powering 4 projectors on that size of image with X-Plane is a real challenge, especially in high density scenery airports. If you can maintain 30 FPS (that is television quality and beyond that your eyes/brain can't tell the difference ) that would be great.  But there is FPS and stuttering and they are different.  If you have a high FPS but get a lot of stuttering, then that isn't solving the issue.

Would it not be better to reduce the size of the screen/image and obtain a view that one would  experience in a real a/c?  It all comes down to personal preference and the simmer has to decide what is important to him.