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making fake cast shadows on uneven background?
I am still a beginner in after effects so if possible, please not use short cut AE terminology on me.
So I had a human figure image sequence animation in a transparent background. I duplicated it, generate>fill it with black and used the x rotation to lay it down to make it look like a cast shadow then further refined it with blur and choke.
Now that is good if the character is standing on a flat ground. But should I put it for example inside a house with furnitures and stuff, the shadow should bend and distort when it falls over the furniture.
Is there a way for me to tweak the fake shadow to look right when it falls on objects in a complicated background?
Please link to me a tutorial if such exists. Thanks.
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2 Replies
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you can try displacement map (effects>distortion) to distort the shadow. displacement map will distort a layer based on another layer’s rgb values.
what you would need to do first, is create a comp to use as a displacement map layer. if you had created the 3d scene in a 3d program you could probably just render out a depth matte that would be a black and white render with the closest objects being white (or lightest) and the furthest being the darkest, and that would work nicely. if you created the scene in ae, or are trying to match it to a photograph (or video), then it will be a bit of work…
if it was a scene made in ae, duplicate the scene comp and start picking apart the layers to make each element a shade of grey. the objects closest to the camera should be lighter shades of grey, and they should get progressively darker as they go back in space. layers that are not facing the camera, like a floor, will need to be like a gradient (or ramp) from lighter to darker as they recede in space.
if it is a photo you are matching up, you will need to create a comp where you have layers that represent the elements in the photo where the closest elements are lightest and the furthest are darkest. you may be able to do that more easily in photoshop. if it is moving video, it will get more difficult to create, especially if the camera is moving/panning.
but once you have your depth matte, bring that into your main comp.
then i would apply the the following effects to the figure sequence:
– drop shadow effect (effects>perspective) with the shadow only option checked
– displacement map, selecting the depth matte as the displacement map
– cc composite, with composite original set to add alphayou can then start adjusting shadow properties like opacity, direction, distance and softness in conjunction with horizontal and vertical displacement values for displacement map. you may also need to go into the depth matte comp and add a levels adjustment layer to ‘clip’ white values to refine how the shadow is cast.
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW -
For a full run down on Displacement in AE, scroll to near the bottom of this page, Aharon has a three part tut there:
https://leaders.creativecow.net/leaders/rabinowitz_aharon/
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