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# Realigning multiple layers to the same object in the center of frame.

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 Realigning multiple layers to the same object in the center of frame. on Feb 3, 2016 at 4:50:51 pm

Hey all first time posting, been lurking for years. Thought I would see if anyone might know of a way to accomplish something I have been manually doing, I just feel like there has got to be a way to automatically do this.

So were I work we film this matrix like camera move. We have an array with 30+ cameras and we sync them all up and move around a subject in real time.

To accomplish this we need to make sure every camera is pointing towards the same object and its in the center of frame. What we currently do is align all the cameras via eyeball to a yellow tennis ball attached to a C Stand. So using our monitors we go camera by camera and point the crosshairs right at the center of the tennis ball. This would then in theory make every camera point at the same object so it would be in the same spot of the frame for every camera as we move around our rig.

The problem is it is impossible to 100% align every camera to the tennis ball perfectly. There is always something off, maybe its the horizon line, maybe its slightly more up, down, or to the side. There are so many variables its impossible without bringing it into after effects to perfectly align them.

So once inside after effects we go layer by layer (each layer being a new camera) and will need to scale, move anchor point, reposition, etc... To make sure they are all looking at the center of the ball. This is very tedious and seems archaic, does anyone know of something that would be able to auto do this.

In my head the perfect software would analyze the frame, I would say to it, make this my center point (I would select the tennis ball) and then click a button that would auto rotate and reposition the layer to perfectly center up the tennis ball. But as of yet I cannot find anything to speed this process up. If anyone knows feedback would be greatly appreciated,

 Re: Realigning multiple layers to the same object in the center of frame.on Feb 3, 2016 at 5:58:00 pm

This is called stabilizing. See here for an intro:

I would specifically point you to the Warp Stabilizer first:

Walter Soyka
Motion Graphics, Widescreen Events, Presentation Design, and Consulting

 Re: Realigning multiple layers to the same object in the center of frame.on Feb 3, 2016 at 6:50:57 pm

Im not trying to stabilize the clip because that just well stabilizes it inside of itself....I'm trying to get the center of 30+ cameras to be the exact same using a reference point visible in all cameras.

 Re: Realigning multiple layers to the same object in the center of frame.on Feb 3, 2016 at 7:05:46 pm

If you don't want the warp stabilizer, you can do traditional point-based stabilization. Once you stabilize, you can move the now-stable tennis ball of the stabilized clip to the center of your frame.

Walter Soyka
Motion Graphics, Widescreen Events, Presentation Design, and Consulting

 Re: Realigning multiple layers to the same object in the center of frame.on Feb 4, 2016 at 3:29:53 pm

Walter, I don't think what your suggesting will help. Each individual clip doesn't need any stabilizing.

John, the only thing I could think of would be to take the first frame of each clip and bring them in as an image sequence, then stabilize that and somehow reference each frame in an expression with each clip having the same layer number as the frame number it's in in the image sequence, though figuring that out (if it is possible) would probably take more time than just lining them all up manually. Though, if you do this all the time, it might be worth taking the time, assuming it's possible.

 Re: Realigning multiple layers to the same object in the center of frame.on Feb 4, 2016 at 4:23:56 pm

Since we're still suggesting stuff:

I suppose I would double-click on each video (open it in the layer tab) and move the anchor point to the exact center of the tennis ball in each video. You'll still have to deal with some rotation from the sounds of it but it'll make life a lot easier with the anchor in the center.

I think if you had 2 points in each camera you could deal with rotation this way as well using an expression to collect the angle between the 2 points.

Mike Sevigny

 Re: Realigning multiple layers to the same object in the center of frame.on Feb 4, 2016 at 5:41:22 pm

[Chris Evans] "Walter, I don't think what your suggesting will help. Each individual clip doesn't need any stabilizing."

Sorry -- I was thinking that the bullet-time cameras had already been stitched together. The first thing I would try is stabilizing the stitched output.

Walter Soyka