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Jesse AngellMore greenscreen questions...
by on Oct 24, 2015 at 3:55:36 am
Last Edited By Jesse Angell on Oct 24, 2015 at 8:30:34 am


I have another AE question about greenscreen work. We shot a music video, where the band is made up by just one girl who plays all the instruments and sings. We shot her doing each of the roles of the band from the same angle and exposure on a Canon XA10, and I think I have the right 3D camera settings to match the sensor size, focal range, aperture and focus. The thing that is bugging me however is that I don't think the 3D camera is at the correct height, and there might have been a slight angle. Here is what I am trying to create:

An infinite plane of tiled reflective glass with a nebula on the horizon, where we can see the entire band of "clones" assembled, playing in sync. The 3D camera will move inwards or outwards depending on the situation, but always at the same height and angle. These shots will only be used a couple of times at different points. The rest of the song is made up of close ups, some moving shots, and another sequence that was shot separately but told in parallel. I'm not having a problem with any of those shots, just this frontal clone band shot. We did shoot each member displaced to the left or right from the center according to the arrangement we wanted (a triangle formation), but I am still not getting what I want.

For starters, the first issue is the background. I am having a hard time creating this scenery, not the nebula (that's the easy part), but the infinite plane of reflective tiled glass. I would greatly appreciate some suggestions here.

The other part of the problem is matching the cameras perspective to the footage. I am wondering if there are any techniques for this? In every shot we have the corner of the greenscreen fomr which I could derive the x,y,z vectors but I have no idea how to use this to match the cameras perspective.

Thanks for your help =)


I'm beginning to think that I might need some third party 3D modelling and rendering software. I've thought about using Blender, but it has been years since I used it, and everything is changed. I also wouldn't know how to import the after effects camera settings and movement keyframes into blender. I know that in blender, it is rather easy to create the illusion of an infinite plane, via the world fog settings, and having reflective surfaces with tiles is not difficult to generate either. The nebula might be tricky, but I guess I could pull it off. I would like to find a way to import my camera from AE to blender, and then render the background without my foreground, so that in AE I can match my foreground to my background, export to png sequences or avi with alpha, and then import to blender.... could it work? Am I overcomplicating things?

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Dave LaRondeRe: More greenscreen questions...
by on Oct 25, 2015 at 2:34:02 am

I gotta ask -- why 3D? Your description doesn't make it sound like you need it.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA

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Jesse AngellRe: More greenscreen questions...
by on Oct 25, 2015 at 9:57:02 pm

Maybe it's just my lack of experience, but I think it would be easier to setup a skysphere (stars and nebula) with a plane that extends beyond the fog range in Blender. I can't imagine how to do this using only 2D elements convincingly. Perhaps I don't need a 3D camera?

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Tudor "Ted" JelescuRe: More greenscreen questions...
by on Oct 26, 2015 at 1:41:33 pm

There's probably more than one way of doing this, but I think you are over thinking your setup.
Think of each "clone" from the band as a 2d card element that you will pace in 3d space. There is no need to match the camera since there is no camera match move as far as I understand and all "clones" were shot static with no move.
The most important will be to match the lighting, blend the elements together and design camera moves in such a way that you will not reveal the 2d of the "clones".
For any infinite surface you can apply Motion Tile on a tile layer and then position that in 3d. Blending the surface with the background using a "fog" layer (2d feathered layer set far in z space).
Any foreground 3d elements you can add to the shot will help sell the realism - use Element3d, ShapeShifter AE or FF Pro, Zaxwerks or the like to add true 3d elements in AE 3d comp.

Tudor "Ted" Jelescu
Senior VFX Artist

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