In a choerography, is it possible to project a video file from camera2 onto the inside of a hemisphere, and render it to a new video file using camera1? I think I need to be looking at projection maps, but I'm struggling to know what to search for.

You could try decaling the first video from the camera point of view, then switching to the second camera.

Thanks, Will. The projection needs to move with the camera. There is a "competing product" video of the effect I'm trying to achieve here (8½ MB)

Gorf-

I've been thinking about trying this effect as well. I think the thing to do is use multiple spheres, one for each camera, and actually rotate the spheres. Let me know if you come up with a working solution.

Ben

How about putting the video as an image on a light, and constraining the light to point out of the camera, like a projector?

that would be most like the demo concept.

I thought I needed front projection mapping like solution 1 on this page but now I'm not so sure, because I don't know if front projection maps will render in any view or camera other than the camera that created them. I was going to test it, but I can't find the feature in v13.

I like the idea of actually creating a projector. I like Ben's idea of moving the spheres, too; although that would mean writing a little program to mirror the camera's movement.

I think that because all the footage is tripod based, nodal footage, you could just constrain the sphere to orient like the camera. I think.

I've been using this sofware for five years, but because I still don't think of the obvious solutions like that, I'll always be a newbie...

an expression in A:M might do it. Multiply the horizontal axis by -1.

Has this experiment gone any farther? I'm hoping to do the same thing...

After much pulling out of hair, I seem to have gotten this working! I'm using a projection map material to do the actual texture. That gave me lots of flexibility in the video placement. For some strange reason the materials' videos don't animate by default though. In order to get them to animate I had to explicitly set a start and end frame.

I'm still having some issues with color balancing and lighting but that's just a matter of tweaking (I think). One odd thing is that for some reason during rendering the frames are not entirely in sync. I have three copies of the same video cast on my sphere and for some reason one of them is occasionally a frame behind the other two.

Check it out!

Click to view attachment

Wow! That's some amazing stuff. I love it

Well done, Eric!

I don't think it's out-of-synch, I think it's just dropping frames. It looks like you're using a different camera for the rendering than the ones you're using for the projection. In a "live" situation, I'd have thought you'd use one of the tracked cameras as a base.

Yes, I'm using a different camera so that we can watch all three merged into on. They're actually all using the same video and the same tracking, just delayed by 2 seconds. I can't figure out why the middle one would drop a frame or stutter.

Are you projecting against a white sphere? Where's your light? Was the real-life camera on auto exposure?

I'm guessing the answers to these questions may have a bearing, but do correct me if I'm wrong...

The sphere is white, and my light is at the center of the sphere. Autoexposure was set, so I know that's a factor as well. I am just surprised how noticeable it is.

If you look at each segment where there's a big difference between two of the three "frames", follow the left hand frame of the two and you'll see that two seconds later, the exposure level is the same as it was for the right frame. You don't notice it when watching normally because the camera is doing what your eyes would do anyway (if it was you panning around the scene).

Are the "halos" round each frame compression artefacts, then? I'd assumed each camera had a klieg constrained to it.