Recently, i came across a few videos of video projections on buildings and have been very intrigued. However, they seem to be studies made with After Effects. This is my favorite video:
Another video that I really like:
These videos look REALLY nice and I wondered how such a projection could be achieved in reality. A problem with large buildings is that you certainly have to use more than one projector in order to get an even, crisp, complete projection of a building and not only parts of it. Additionally, it would be nice to have generic content of the projection instead of prerendered content like AfterEffects videos in order that the projection can interact with the architecture dynamically.
If video projectors are placed in different positions the projected image on the target (in that case the building) will be distorted. So you will have to distort the image by applying a transformation to it. You can do this automatically like Johnny Chung Lee did:
Anyway, it could be quite complicated to do this like Johnny did with different sensors in the projection surface as a building is a bit larger than a sheet of cardboard. However, with a combination of a camera perched on top of a projector there should be means to analyze projected patterns from the corresponding correctly and to calculate the transformation of the video correctly.
Additionally, there is also the possibility to apply all transformations manually. That doesn’t even seem to be too complicated and the amount of projectors used in such a project isn’t too big. A way to do this is illustrated by Christopher Baker as can be read on digitalschweinshaxe.net (thanks for the hint nico):
As far as I understood, the application MawLib from Christopher is written for Max/MSP/Jitter and is based on OpenFrameworks (OF) and the source can be checked out here. I do not know much about Max/MSP/Jitter but if MawLib is really based on OF it should be easy to be ported to a stand-alone application.
I will see if I get the opportunity to work with such projections on buildings. Should be lots of fun!