For our last VFX document we will be taking a look at a set of Blender features and scene-building methodologies which I think a lot of people take forgranted. Or if you are like we were before 2010, too intimidated to really look into.
This is the document covering the topic of scene layering and the use of Blender's render layer management system to manage render times separately per element through the use of built-in masks. There was a time we considered emulating how some early CG films were done with separate specular, diffuse, and shadow passes. But as testing progressed, it didn't seem to make sense on this current production to do that. However, what did make a lot of sense strategically was to render in layers that allowed us to make changes very late in the process without affecting parts of scenes that didn't need changing.
This meant that re-renders and detail-fixes were highly managed. But this approach was also important in ensuring each layer (and by that logic, each effect) could be rendered in its own time, manipulated, enhanced and associated nodes and calculations could be done before all layers were merged per shot for best results.
This Layered Images approach, while it sounds simple enough, is actually integral to many of the Visual Effects on-screen in REVERSION. Early on, there is a pretty convincing "mirror reflection" effect that was attained by using layers cleverly inverted and placed within other surfaces, preventing us from having to use time consuming Ray Mirror calculations.
Here is the final VFX Document: "The Render Guide"