When I was putting together Neptune, the dome for the Modular Art Pods show, my biggest struggle was to sort out how to project in my dome on a budget. A very tight budget.
I was thinking that it would be best to come up with a solution that let me put together multiple small computers and send signal to all of those computers so that I wouldn’t have to buy a big, expensive computer to run the show on. I wrote code obsessively for about a month, when I wasn’t at work – got a network switch, and hit a wall when I realized I don’t know the first thing about networking and didn’t have time to learn about it AND create content.
There are solutions out there that work (Blendy Dome VJ exists, and it’s great – but if you don’t have a budget, you can’t buy neat things.)
About a month before I had to install the dome at the show, this lovely little piece of software called Omnidome came out. It’s free. It’s powerful and It works very reliably.
What it does, specifically, is split up the video for multiple projectors. I run my video in QLab, but you can use any softare that has a Syphon output. I should also note, that I’m using a Mac for all of this. (You can use it for flat mapping as well as spherical. It’s pretty handy.)
If you’re using Omnidome, you’re going to need to either have a computer with multiple VGA, DVI or other outputs OR get a Matrox Triplehead. This device allows you to fool your computer into thinking that it has one extra wide monitor – and the device actually splits it into 3 different images for 3 different screens… or in our case, projectors.
I use VGA in my dome. It may seem like that’s antiquated – but if you don’t have a blazing fast computer and your outputting to 3 projectors, you can’t handle HDMI. (I’m a big fan of the “get the darned thing running even if it’s not perfect and super cutting-edge” approach to things.)
You need to learn a little about how cables work. There are a billion types of DVI cables, it seems. Some pass an analog signal along and some do not. If you’re trying to work with DVI and VGA out of the Triplehead, you HAVE to pass an analog signal across your DVI cable or it’s not going to work.
The computer I used for the show was a 2008 iMac that I picked up for slightly over $200. Is it fast? No. Does it run the show fairly reliably and am I ok with leaving it in a place where the public may potentially mess with it? Yes. If it got damaged in transport, would I be upset? A bit. Am I going to get something faster as soon as I can? Absolutely.
The bottom line: you can spin up a planetarium of your own for under $500, and Omnidome can run the thing very VERY well.
I’ll get into the interface a bit more in my next post.