TimeMap tech video

Hi there,

Jonas and i just shot this little video for you guys from our coding of software for TimeMap #3, a Recoil dance performance, premiering this April.

It’s a slightly overworked me that’s talking, and i had to cut severely to get rid of the all to many 'eerr’s and 'rrrhmm’s - hard to talk human when you think c++ :shock:

it’s the most complex setup we’ve been doing so far - and from today we are in a rehearsal space with the dancers.


Hey Ole… cool video! What you are doing here looks to be using concepts that I will be experimenting with in a couple upcoming projects.

The one part that really stands out and interests me is your beautiful multi-headed display setup. I am very interested in the hardware and software components you are using to synchronize the monitors like that.

We were thinking about a setup that would use several computers/projectors, with each one responsible for a different section of the display.

Could you please provide links or more details about what you are using for your multi-display setup?

Thanks so much!


the computer is a mac pro stuffed with screen cards. i.e. 8 dvi ports on the back.

on the first dvi port i have put a matrox tripplehead2 go, which splits a 2400 x 600 dvi signal into three seperate 800 x 600 feeds. this is what i use for the openframeworks rendering, as non-sli ATI graphics cards would otherwise risk clogging the bus, when one card would have to send raw pixel data to the two others… in this way i have one fullscreen openframworks program running 2400 x 600 resolution. in this software i rotate and skew the opengl matrix to provide three rotated and keystoned viewports on one canvas.

these 3 feeds are then connected to a meicheng 8x8 vga matrix along with another set of three individual dvi-ports, directly from the remaining three dvi ports on the two first ati cards, where 3 rotated 600x 800 feeds come out.

in this way i can have 6 screens rendering opengl and isadora but still use the two lower ati cards, meaning i have full 16x lanes pci bandwith.

external monitors, the desktop on a hd display and an osc server on a small monitor (not in the video) are not routed throug the matrix, and are connected on the two remaining ati cards, that only carry one display each, as they have 8x pci lanes.

the meicheng matrix is cheap and crude, it does not provide syncing of the vga signals - it simply reroutes the raw signals.

it has a simple serial protocol, and accepts 8 byte long ascii commands, which it confirms. it can be polled for its status. i have isadora poll status and update screen routing as neccesary throughout the show.

as the signals are cut without sync i have to give the projectors time to resync whenever i do a matrix rerouting. the projectors are cheap, but strong acers. unfortunately they insist on showing all kinds of osd and logos, while resyncing - while this happens i simply cue dmx-controlled shutters for the projectors.

hope that was helpful.

/ ole