Extracting different faces from a Cube Map Render

Beginners
1

Good morning !

I want to project on 4 video projectors (1920x1080) in a room. To do this I use a cube map rendering followed by a Projection TOP. Could you help me extract the 4 horizontal faces on camera? I’m not interested in what’s above and below. I cannot obtain correct extractions in terms of resolution and aspect ratio.

Thank you so much

2

So I tried two methods:

  • The first was to place 4 cameras phase shifted by 90° around the vertical axis with a horizontal FOV of 90. The problem here is that a natural distortion occurs when you get closer to the edges. A Lens Distort TOP would not solve anything because I want to have continuity of points during projection.

  • The second is to use the Cube Map. However, I observe a significant difference in quality unlike the first solution (perhaps my TOP and Crop Projection parameters are poorly adjusted)

test.7.toe (18.1 KB)

3

Hi @schubhan.arv,

just thinking out loud, but when you try to project a donut onto the inside of a box, there must be distortion as the walls of the box will be closer to the donut in the corners. Viewed from the center or a sweetspot of the room, it should look correct for the viewer.

Just recently looked at that and to fit things into non-square rooms made use of the Quad Reproject feature in the Camera COMP.
Here is a test using an adapted Quad Reproject COMP from the palette. But yes - always just correct from a sweetspot.
QuadReproject.17.toe (10.3 KB)

cheers
Markus

4

Indeed, the projection of a donut on a box creates distortion. I observed the rendering in 2 dimensions… while placing a camera in a new geometry simulating the projection walls. Indeed it works. So since yesterday I had succeeded haha.

The fact that I don’t come from this background sometimes plays tricks on me. Thank you very much in any case!

Will I be able to change the scales of the renderings with QuadReproject if the walls are not exactly the same size?

Cheers

Edgar

5

Hi @schubhan.arv,

i had the same issue - it looks wrong on first sight.

You can change the size of the walls to whatever you need. Biggest issue you might encounter could be the overlap between the different projectors in the corners of the room. Don’t really have a suggestion right now how to deal with that though. Maybe knowing the size and shape of the overlap would allow you to create separate geometries for each overlap and then assemble them manually.

cheers
Markus