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Compositing actor to 3D virtual set
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If you use a Shadow plugin like Wrap/Shadow, you need to animate the shadow end to change perspective with the scene. If you use a 3d duplicate of the 2d actor layer, once it’s positioned correctly it will move with the floor as the camera moves.
Tudor “Ted” Jelescu
Senior VFX Artist -
How to professional companies do this? Do they use something like the red giant plugin? I don’t think it is possible to get the shadow correct if the layer is 3d. I think that the shadow layer must be 2d, and 2d motion tracked to the feet, would this work?
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You helped me with the previous problem, but the new problem, as describe is the shadow
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Shadows in 2.5D situations are never as straight forward as you would like.
I don’t know if you can use the same projection techniques in After Effects that you can do in Nuke but if you can here is what I would try:
Work out where in the 3D space the actor should be standing and position a 3D layer at that point.
Key they actor so he has an alpha channel.
Then project him from the tracked camera, onto the card. This will give you the actor in the correct position in the 3D space and at the correct scale. This is that part that I could do in Nuke easily but I don’t know how you would go about it in AE so someone else on here will need to chime in. I’d like to learn if this can be done in After Effects.
Once you have the actor on the card you can use a light and that card to cast a shadow onto the other geometry in the scene. You could either use this as part of your render, or render it separately and use it as a mask to grade your BG through. This is where AE wins over Nuke at the moment. You can’t cast shadows in Nuke so this doesn’t work.
The short coming of this technique is that that card is only 2D in a 3D space. The shadow will look great if the light is from the front or the back, but it won’t work at all if the light is 90 degrees to the card because there is no volume.
I most cases we use 2D tricks to create these kind of shadows. If we need a more accurate version we would get a match moved digi double of the actor, place it in the 3D scene, and render a shadow matte from the 3D package.
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I will consider all these option, and thanks to all for helping me one step closer to the solution
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[Evan Robinson] “How to professional companies do this? Do they use something like the red giant plugin? I don’t think it is possible to get the shadow correct if the layer is 3d. I think that the shadow layer must be 2d, and 2d motion tracked to the feet, would this work?”
Generally I’d expect high end productions to do a separate key to pull the shadows from the green screen.
Darby Edelen
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