In one week our work on the BCC Innovation Festival will culminate in an hybrid event, whose physical manifestation will be held in the Salone delle Colonne: an impressive looking immersive room in Rome’s EUR district.
We are tasked with producing audiovisual material that shows off our immersive experiences in a context that is still immersive, but not interactive. In practice this means producing 360 videos, which have fewer rendering constraints (they don’t have to be executed in real time on random devices), but in which the visitor is less able to look around and explore.
We’ll make sure to share this video when it is done, but for now I want to share how we managed to preview how the projection was going to look, without going all the way to Rome to try the system out in advance.
First of all we took the floor map of the space, which was available as a PDF on the venue’s website, we imported into Blender and we modelled a very simple mockup, using just cylinders for the walls and columns, and planes for the ceiling and floor.
We also put in cubes to represent the positions of video projectors, but we didn’t bother to scale them correctly. We also didn’t model the sort of “steps” with which the ceiling lowers towards the sides of the room, as they don’t interact with the projection geometry.
So far this was all straightforward modelling, the only somewhat non-obvious thing we did was mapping the 360 video onto the screen.
We added a new material on the walls cylinder, with an Image texture obtained with an equirectangular camera in our Innovation World Blender scene. (Note: equirectangular cameras only seem to work in Cycles)
Going into the UV Editing screen in Blender we put a seam on a vertical edge of the screen, and we did an UV > Unwrap. Then we selected all faces, and scaled them on the UV side until the seam matched perfectly. We can then change the center of the projection by moving the UV faces on the X and Y axes.
We put the resulting Blender file and a GLB on our site, and we also stuck it on Sketchfab for ease of use. We should do a three.js version in which users can load their own files and play around with the projection parameters.
Geometrically the problem is that the equirectangular video we make in Blender goes from +90 to -90 degrees on the vertical axis, while in the Salone delle Colonne there are something like 29 degrees of vertical elevations, if we look from the center of the room. Actually considering a standing spectator it’s something like +18 to -9 degrees.
This is of course assuming that the projection has been setup correctly in the room itself. I think ideally the venue should provide examples files, but after all it is a very new installation.
Similarly the projectors themselves are very advanced, they have an automatic edge and overlap system that we’re very curious to see in action, but it is not quite clear what the logical resolution of the system is.
Very interesting stuff!
Edit: I’ve found this article with more technical information on the room’s video system: https://www.sistemi-integrati.net/proiezione-immersiva-di-grande-impatto-nel-salone-delle-colonne-di-roma/
Edit 2: brief video render