Multiscreen Projection feasibility

[jonredraggle234]

Hi folks, 

I'm new to VPT.  My project involves using a single computer to project to multiple projectors.  The mapping is fairly simple - a single source adjusted slightly to match the room (in 2D).  To clarify, I'm projecting a single video onto multiple 2D rectangles from each of three projectors, from the same computer (windows 7, higher end computer, video res = 768x1024).  

Is this possible with VPT?

[hc]

Hi,
this is possible in VPT using a matrox triplehead2go which expands your output to three screens.

[jonredraggle234]

I should mention I have three screen output capability on my desktop (3 DVI / VGA).  Given this, would it be possible wihtout the Matrox Triplehead2go?

[hc]

no,
VPT only support one screen output.

[TommeeT]

 I use a Matrox TH2Go with VPT all the time and it works fine. Just need to make sure you assign settings to two or three screen first.

 Also sometime you need to arrange the overall display output settings of your computer first in the Matrox PowerDesk tool.

 Good Luck…

[jbrem]

HC,

First off, congratulations on the release of VPT 7. I'm enjoying the updates to the program quite a lot. I am curious to know if support for multiple screens is in the future of VPT? For me, as a theatrical video designer, it is the one deciding factor between using VPT and most other software at the moment (Watchout, Pandora's Box, Isadora, D3, etc...) and I feel this addition would really put VPT in the running for larger scale projects. Keep up the great work!

-JB 

[hc]

it depends how you define multiple screens. I and many others use VPT together with matrox triplehead2go to get 3 outputs. Possibly it would also work with ATI eyefinty as well, would be great if somebody could test that.
Apart from that there is no multi-screen support in VPT.

hc

[jon bremner]

Thanks for the reply. I do use Matrox units frequently to help expand smaller machines. If you try and do any edge blending though, for larger-scale mapping projects, it just doesn't quite work out. Was mainly interested in seeing if this was something you were considering or not.

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Jon Bremner

LucidDesign
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[hc]

I have to leave some festures to the pro apps that people pay $$$ for :-)

[jon bremner]

haha, fair. Wish some of the pro apps took some cues from affordability and mapping capability that you've managed to add.

-J

[hc]

on the other hand, never say never. It´s something I explored a bit in the early stages of VPT 7 so maybe I will get back to it at some point.

However, the  plan is to make sure the current release works as expected for most users, not to add new features.

[Ariel Kalinowski]

Sorry, just asking for clarification here:

does this mean you can't generate multiple output windows with a triple head?

I'm trying to "stack projectors" so that I can get double brightness; I think I have to send a different image to each projector, and then map them on top of each other.

[David]

On Saturday, 4 June 2016 08:35:24 UTC+1, David wrote:

Hello Ariel,

The triple head takes one big image and cuts it into 3 pieces horizontally, with one output each for the pieces........ left, centre and right.

For double brightness you need to align the projectors as perfectly as possible and they must both receive the exact same image.  Reset both projectors and physically align them before using the keystone and any other tools offered in their menus.  This can always be achieved if you think about the geometry.  For any lens they should be stacked one above the other with enough separation for efficient cooling, at the exact horizontal centre of the screen.  If they are short throw lenses they should be as close as possible to the vertical centre of the screen, and if they are long throw lenses they should be aligned with the top or the bottom of the screen.

((Beware ------ If you cannot put them in the correct place, and you shift the image (lens shift or electronic shift) by a great amount you risk losing part of the image to the lens surround.))

It is best if the projectors are on flat surfaces.  If they are suspended it much more difficult, and they can move unexpectedly during alignment.

Obviously only one of them can be in that place.  Find the correct place for that projector, moving it physically (all electronic parameters at "zero") until you have a perfect image.  Make sure that the screen is perfectly vertical and not twisted horizontally ( at 90 degrees to the shortest beam path from the projector in both planes), or you will not succeed unless you have very sophisticated projectors (in which case you would not be asking this question).  You will see immediately if the screen is incorrect as the image will not align.  If the projectors have to be in the wrong place that is no longer true.

Then align the second projector (the one that is not in the correct place) with the first.  There are always faults with the alignment of the plate and the lens.  For this reason you might find that the second projector needs to be slightly to the side of the first (horizontally).  Start by getting the horizontal line (lets call it the "reference line") that is in the plane of the projector (centre for short lens and top/bottom for long lens...... 0.8 is short...... long lenses are usually zooms) perfectly aligned with the first projector.  Use the feet / suspension tray for that........ always physically align before going into the menu.  Look at the sides of the image.  If the difference in the vertical edges is different then move the projector right or left until the difference is the same.  Now use the keystone and the physical / electronic zoom as necessary, adjusting the projector front/back feet at the same time to keep that horizontal reference line aligned.

I spent 20 years doing exactly what you want to achieve, every day in a different venue with different projectors.  It is always possible.  Some projectors have horizontal and vertical keystone, and some can map the whole image, which allows for some very funky projection angles, but if the geometry can be perfect then it is easy.

David.

[suji...@nid.edu]

Hi

I am working on a 40ft x 40ft interactive game for a college project. The game is projected on the floor and players interact with digital elements.

I was wondering if I can project the single game screen developed using processing (processing.org) with 2 projectors without any noticeable skews.

Please suggest / guide. Sorry if this is a noob question.

Thanks
S

[David]

Hello.......

All projectors have "keystone adjustment" which you can use to correct "skews".

The geometry is important.... the better you can place your projectors the better your chance of a perfect image.

Projectors that use a prism to adjust the keystone will be best, as an electronic adjustment will give ever larger pixels as the distance to the image increases, and jagged edges.

The more keystone adjustment you apply the smaller the image will become.

I would suggest playing with a projector to understand the concepts.

The image can be split and adjusted in "processing" but it will suffer the same problems as a projector without prism adjustment.

The "split" to the two projectors will be good though, and you can "edge blend" the split images.

David.