As we approach the final deadline, it's of utmost important that I render the CG sooner, rather than later, to give the compositors enough time to work with the footage and properly integrate the 3D elements.
Using Yachan's camera track for shots 1 & 4 (shot 4 leads directly into shot 1), I rendered 1400 frames of the obelisk CG using 5 layers.
Beauty. This layer is to be pasted over the top of all layers except shadowproject. It's the diffuse and specular of the textured obelisk model.
Shadow. This layer is the shadow of the obelisk that falls on the sand behind it. While the color is black, the above gif shows the alpha of the layer. This alpha will be used in compositing with a grade node to darken that area, giving a realistically cast shadow.
Reflection. In the location we filmed, the ground was a reflective stretch of very wet sand. This reflection layer is needed not only to match the scene, but also to cover up the reflection of the tripod we planted to give the actor reference. I warped the ground geometry to give a similar distortion as the one we see in the ground reflection of the live action plate.
Reflection Mask. Because the reflection is a reflected version of the beauty layer, we need the lighting to match the beauty layer perfectly. This includes displaying our HDR. The specular data from the HDR is necessary, so we can't turn off its visibility. The red obelisk reflection is our model given a pure red Maya surface shader. This red channel can then be used as the alpha for our reflection layer, showing only the pixels of the obelisk that get reflected.
Shadowproject (Shadow Projection). This layer is the projection of our actor onto the obelisk. It was created by Yachan providing me with a skillfully created roto layer of our actor cut out onto the scene. With 31 position keyframes, I moved the plane of the alpha of our actor to match how close he was to the obelisk. It's not perfect, because it isn't a realistic perspective of what the shadow would look like given the light direction, but it does the trick well enough to fool an untrained eye and sell the integration.
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