Printable View
Has anybody had any experiance of using Cats - or Multiple cats or even a THTG to provide a singnal for projection onto a large globe.
I believe we can cover the required 270 degree coverage with three 25k projectors slightly below the C/L off a 24ft Dia globe.
But -- and its a big but .....Will it be possible to creat content and then to split and warp content to acieve a projected globe Fx...
regards
Ian H
Just did a 5.5m (18') Sphere with 360 deg coverage.
Kind of worked!! As a test we put a world map in the wrap rotate function and we got a serviceable rotating globe. I just downloaded one of the numerous world map textures you can find online. Any imagery that travelled from Left to Right/Right to Left looked good.
Mapping onto the sphere was time consuming and quite the learning curve. We used 6 projectors with 2 x THTG off one Mac Pro. I found that finding a good mapping preset for the first projector mix and then copying that to the other projectors worked best. We then went around and matched the edges of each blend as best we could.
For the show we generally just did texture and a small amount of scrolling text so our line-up was fine but could have been better if we had spent more time (always the way). As a first attempt we were happy but I know we had a lot further to go to get it right.
The most important thing is to understand the relationship of the image size to the surface of the sphere. The image size is not as simple as the circumference of the sphere by its diameter. This might be obvious to others but caught me out. See attached pic.
We used the top and bottom blend function to get a soft edge where the image fell away so we didn't have ugly hard lines.
Hope this helps.
Cheers
Toby
thanks for that..
we are hoping to do some scale tests shortly -- will be interesting to see what we can achieve.
ian
Axis is very important. In a world view, the closer you can keep the center of the globe in the same plane as the projectors, the easier the blending will be.
I did something a few weeks ago with a smaller globe. Toby is right, it's a pain in the ass.