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How to Create Scrim Panels that Move

Panels are vertically mobile for creator's Seeds Conference

Rose Brand congratulates our sixth blog contest winner, the team at Church on the Move. Their blog entry described how they built  scrim panels that are vertically mobile for their Seeds Conference. Here is how THEY did it...

We kept it mostly low-tech (emphasis on mostly) with technology we already knew how to operate and sort out. The impetus for keeping things simple was pretty much culled from self-preservation as we knew the one time we didn’t really desire major technological issues was the opening of our first Seeds session. Go figure.

These 6 sharkstooth scrim panels were custom fabricated out of some larger pieces we had used a few years ago – a local company was able to make this happen for us but scrim material is available in almost any kind of custom size at Rose Brand.

The objective of this element was to project 6 different images on 6 different scrim panels that could raise/lower as needed. Due to the heavily populated stage area overhead, working out the mechanics of the manual raising and lowering process proved to be the biggest challenge. Although not completely groundbreaking, here’s a brief breakdown on how we made it work out for our needs.

To give us a starting point for both the raise/lower mechanism and a place to tie off the actual scrim panels we mounted (6) horizontal runs of uni-strut on the ceiling hanging exactly where we wanted them to hang. Using pulleys in some strategic positions, we used nylon parachute cord that ran from our six “custom” (ahem–homemade) winches mounted on the catwalk, up to the ceiling, over to each scrim area, and then down to the scrim itself. Here’s a few photos to illustrate:

As for the winch, it’s essentially a wooden box with a reel in the middle that would wind up the parachute cord without too much or too little friction. Didn’t want it to be a huge struggle to wind up while raising and didn’t want it to have the tendency to free-wheel when lowering. Powdered graphite came to the rescue to keep the reel lubricated within the wooden box and between the nylon cord and the pulleys, the friction point was fairly easy for our stage crew to deal with. You can see that we installed a stop of sorts so when the scrim was set to the desired height, you could pull out the metal peg for the handle to rest against with no continued rotation. This made it an easy maneuver to operate: the crew could move the scrim up or down, pop the stop into place and walk away secure that everything was locked down and stable.

The scrim itself was equipped with grommets spaced 1’ apart all across the top edge and down each side. The grommets at the top were used to tie each panel to the uni-strut and all the side grommets were affixed with a snap-link. The snap-link allowed us to run that continuous piece of nylon from the winch upstairs all the way down through the snap-links where it was tied off. At the bottom, we put a piece of 1” conduit through a sewn pole pocket in the bottom of each panel. This gave us a little bit of rigidity without adding too much weight.

For projecting, we used six Barco R-12 projectors. We’ve used these quite a few times and the 12,000 lumens have always delivered a decent punch while still being pretty easy to setup and operate. Finding six that had similar hours on the bulbs was a bit of a challenge but projecting onto scrim vs. screens gave a little bit of latitude in how they were all matched. We flew these on three different trusses positioned around the room that were all about 60’ out from the scrims. Our video engineer spent some time dialing in the edge-blending on board each projector to soften the projected hard edge of the image area. This created a nice drop-off to the edge of all the projected areas.

Getting the content to the projectors was a bit more complex as we had to send six different video feeds with different content on each but still remaining in sync with each other. Having used Catalyst media servers for quite some time it was a natural choice. With the Catalyst, each server has only one physical output or two if you don’t mind sacrificing your reference monitor. In order to keep the reference monitor intact, we used a couple of Matrox TripleHead-2-Go’s. This device can take one video input and create three video outputs–these are not actually three separate signals but separate sections of one display that is three times the normal width. For example, if the input signal has a resolution of 1024x768 then the output signal will be 3072x768. Output 1 would use horizontal pixels 1 thru 1024, output 2 would use 1025 thru 2048 and output 3 would use 2049 thru 3072. With the Catalyst’s ability to create internal video “mixes” (windows in the program that act as separate video outs), and the TripleHead units, we were able to meet our playback needs with only two media servers.

A bit of clarification on the Catalyst. A Catalyst media server is a Mac Pro computer utilizing Catalyst software. Although this software is complex, the computer setup is still relatively basic. The signal path for each media server (routed to three projectors each) is as follows:

  • Output 1 was a simple DVI reference monitor and output 2 was our signal to the projectors–this output first hit a TripleHead where it became three VGA outputs, then each VGA went to its own analog video DA (1 VGA in x 2 VGA out). The TripleHeads must see an EDID signal to function properly so output 1 on each DA went to a VGA monitor and the DA output 2 was converted from VGA to 5-wire RGBHV that was sent on to the projectors.

It made sense to set the Catalyst rigs up near the GrandMA in lighting world since that was what would be controlling them and design-wise it kept everything in the same sandbox. This did add a bit of complexity to the lighting control area. Check out this picture:

When it was all said and done, we had put in enough pre-production effort to wrangle in most of the obvious problems that reared their head. The technology was kind to us and our crew did a magnificent job of dealing with the winches. The result was exactly what we had in mind.

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