[ANSWERED] Stacked Projectors/Beamers

[jrhooker]

hi community!

i'm in a situation new to me, but I think this is a pretty basic question...?

I'm designing projections for a play at a university. They don't usually do projections (etc etc etc) and they have pretty small projectors for the size of their space. So, we want to stack two for brightness. I'm not allowed to touch the hardware (frankly fine by me) and OF COURSE they've given very little time for projections in tech. They're hiring a media company to deal with the stacking. I've honestly never had to stack projections. My question is, can this be done easily only on the hardware side and can I then just set my patch so that it's basically duplicating everything using each projector as a different stage. Or is the only way to do it through Izzy map. What are the best practices here? I saw a 2017 post by, I believe, @woland with instructions for how to do it via Izzy Map, but I'm just curious if there are hardware-led ways to do it instead...because I'm worried about my tech time. 

The projectors in question are: Pro G7100 XGA 3LCD Projector with Standard Lens

Thanks!

J

[Woland]

@jrhooker said:

I saw a 2017 post by, I believe, @woland with instructions for how to do it via Izzy Map

I was reading this post and was like "Oh yeah, I did this with IzzyMap super easily a while ago" and then I got to this part XD

Was dead easy though. Just turned on the projectors, spit out the same test pattern from both, then remote controlled the show computer with my laptop so I could be right up onstage fine-tuning IzzyMap to make the two images overlap. After that, stick the mapped Projector actor inside a User Actor, add it to the document toolbox via the right-click menu, and then you can use the mapping across your entire project and even adjust it globally in the event the physical projectors get bumped or moved.

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@jrhooker said:

I'm just curious if there are hardware-led ways to do it instead

In my experience, the hardware-led solutions for this don't work with just any projector. There are fancy projectors that have special settings that allow them to be stacked to increase brightness which do the compensation either themselves or via special software on the connected computer. It's been a while since I needed to do this though, so maybe someone here knows of a more recent development that's feasible and hardware-based.

[DillTheKraut]

@jrhooker said:

Pro G7100

 Reading the Specs of the Projctors, they have shifting and support image warping. I don't really know this specific Projector and how well it works, but i did work with a bunch of epsons older and newer series. They usually have a good software integration (Firmware with well thought control features).
It all depends quite a bit on the projection surface you are going to project on. If it is a very plain, single colored screen, and the projectors are close together, you'd probably be easily done with the shifting function of the projectors. A professional projection tech should be able to put those pictures together with this easily. If you know the true basics of the shifting feature and how it (physicaly) works, you could even do it yourself.
If the screen isn't plane or the physical matching is not possible (maybe the projectors are to far away), you could use the internal warping. This is basically a simple version of the izzy map warping feature.
Why using the projector internal features instead of izzy map? The most important reason is the number of output lines. With the matching by the projector itself, you'd only need one output and one long line to the projectors. This signal line would be split by a simple 1:n distributor close to the projectors, which should stay as close together as possible. Going by the izzy map way, you'd need a dedicated output and signal line from your computer to the projectors.

If the the Tech support claims, it can do the matching within the projectors, i'd probably trust them (Actually I'd help or do it myself). The projectors a at least capable.
If the Projectors are as close to your laptop that you can easily provide the signal lines to each of them, and are unsure about the support on side, do it by Izzy map, but prepare your show for it beforehand!

[Fred]

@dillthekraut said:

Pro G7100

 I have done stacking with no software with high end Panasonic projectors, they were in cages that had fine adjustments for height and rotation on every axis. It was not too difficult to get things lined up and the signal could daisy chain through them. 

This is obviously much easier with minimal image warping on either projectors, but high end models have fine adjustments and corner pinning that makes this pretty easy. If the tech team are going to do it, then let them do it. 

Although these have a test pattern generator, I would make some complex test pattterns for them to line things up accurately, One (annoying to make) would be an imager at the native resoltuion of the projector with alternating lines of R, G and B pixels, you can cut the image into 8 sections and alternate vertical stripes and horizontal. This will make it easy to see if the pixels are spot on as the colours will change if they are not.

All in all stacking with hardware is a tried and tested way of getting more brightness and if the team knows the gear well let them do the work.

[DillTheKraut]

@fred said:

Although these have a test pattern generator, I would make some complex test pattterns for them to line things up accurately, One (annoying to make) would be an imager at the native resoltuion of the projector with alternating lines of R, G and B pixels, you can cut the image into 8 sections and alternate vertical stripes and horizontal. This will make it easy to see if the pixels are spot on as the colours will change if they are not.

 Especially Panasonic projectors (they where my main job machines), have an internal grid pattern which can be set to one of the rgb colors. If you set one projector to a specific color (eg. red) and a second to another (e.g. green), they mix to a third color (e.g. yellow) if they perfectly match. This makes it very easy to identify miss matches and even the direction to shift/warp.

Some projectors offer the option to set the whole system to one of the RGB basic streams. This way every every test pattern becomes monochromatic.