Lynda.com just released After Effects: Light Transmission, a short video tutorial set by Trish and Chris Meyer:
"Projecting one 3D layer onto another is useful for creating film and video projections as well as stained glass effects. In After Effects: Light Transmission, instructor Chris Meyer demonstrates the required steps, including mastering shadows and the Light Transmission parameter. He teaches numerous tips and tricks for building 3D worlds (including using seamless tiles), grouping together layers and lights, softening or sharpening projections, and using "negative light" to remove unwanted light leaks from a scene."
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This set appears to be the funner video counterpart to a text-based tutorial at Artbeats mentioned in the recent post AE tutorials for projecting, reflecting, & arranging 3D layers.
Update: Lynda.com is also carrying After Effects Natural Light Effects, which tackles "volumetric lighting effects, such as light rays and glows, [which] are susceptible to two common problems: They can look too synthetic, and they are prone to banding when compressed for DVDs and the web. ...Chris Meyer shows how to make light look more realistic by adding dust or swirling smoke, creating natural imperfections that help with compression. He demonstrates how to do this using stock footage of this natural phenomenon or the After Effects Fractal Noise and Turbulent Noise effects."