“I got a couple of tough shadows to deal with.''
“There are shadows in life, baby.''
-Jack Horner (Burt Reynolds) in “Boogie Nights”
25 years ago, my high school cinematography instructor made us watch a short film way out of focus. At the time it seemed absurd, but he was trying to get us to notice light/dark densities and how they break up the frame.
I have learned a lot from my gaffers over my years of live action shooting. Simply putting a tree branch in front of a light can create interesting and beautiful shadows on an otherwise plain wall. The trade name for this light obstruction material is cucoloris or “cookies”. These are boards with shapes cut out that are used to cast light patterns. They come in a variety of patterns but I tend to stay away from clichés like windows and Venetian blinds.
These same practical techniques can be applied in the After Effects 3D world. All we need are lights, obstruction layers (cucoloris) and surfaces to shadow. This tutorial is broken into two parts that highlight two examples of dressing up a scene with shadows.
For the Walter E. Smithe Furniture “Lamp Battle” spot, I captured Mark and Tim Smithe battling in front of a green screen since we didn’t have the budget to create a cryptic marble fighting arena.
Instead, I built three marble walls and a pillar in Photoshop and brought them into After Effects.
You can make your own digital cucoloris in Photoshop by cutting custom shapes from a solid layer or you can take a still photo of a tree branch against a blue sky and key it out in After Effects using Keylight. I blurred the branch a bit to soften the edges and saved it as a Photoshop still to maintain transparency.
I made a rotunda from the three walls in 3D space. As you can see, the bare walls look unappealing until we break them up with shadows.
I added my cucoloris tree branch as a 3D layer to the scene along with a spotlight focused on the back walls. In 3D space you just need to position the cucoloris in front of the light so it casts an interesting shadow on the wall. Make sure it is far enough behind camera so it doesn’t sneak into frame.
Remember to turn on “Casts Shadows” in the light options and make sure your wall layers have “Accept Shadows” turned on under material options. I turned off “accept lights” for the walls. I only wanted the shadows for this environment.
You can reposition the tree branch until you find the perfect shadow castings. Also notice the nice shadows from the pillars that are positioned away from the back walls.
I wanted more control of the light/dark densities in the scene so in addition to the tree branch shadows, I added a shadow mask layer to further darken certain areas.
For this I created a solid black layer and drew a few masks with “subtract” selected. I positioned it above everything else but below the actor layer. This setting will allow full brightness of the underlying layers through the mask holes. I softened the masks with a 30-50 pixel blur. I also brought the opacity of the layer down to 75%.
The shadow mask is a simple way to quickly tweak the light densities of your scene. Keep in mind that if your scene is animated as in this case you may need to key-frame the masks to adjust to the motion. You'll find that with the mask’s soft edges, tracking motion is more forgiving.
You can also add your shadows in Photoshop to save some work and render times in After Effects but they won't allow for real environment shadows from pillars and the like.
This spot has a smoke layer on the ground and a fire layer on the wall to help flesh it out but the shadows contribute the most in adding realism.
Click here to watch the movie
In part two we will cast some long shadows and as a bonus I included a recipe for creating smoke and snow.
Bill O’Neil
Go to Bill's site to see more of his work: www.chicagospots.com
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Discuss this technique or others in the After Effects forum at CreativeCOW.net.
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