This page gives an overview of the Reflection Filter Render Element and explains how it is used.
The Reflection Filter Render Element stores reflection information calculated from the materials' reflection values in the scene. Surfaces with no reflection values set in its material(s) contain no information in the render pass and therefore render as black.
While the VRayRawReflection Render Element gives the full reflection of objects reflecting in the scene, VRayReflectionFilter shows how much of that reflection should come through in the composite. In other words, the filter defines the strength of the reflection, while the raw image defines what is being reflected in the image. When these two elements are multiplied, the true level of reflection is given and produce VRayReflection. Using these component parts of the reflection, you can better fine tune the reflection in your final composite.
The Reflection Filter element is a sub-component in the main Beauty Pass.
This render element is enabled through the Render Elements tab of the Render Setup window in 3ds Max and displays its parameters in a rollout at the bottom of the window:
VRayVFB – When enabled, the render element appears in the V-Ray Virtual Frame Buffer.
Deep output – Specifies whether to include this render element in deep images.
Multiplier – Sets the overall intensity of the render element, where 1.0 is the standard multiplier.
Denoise – Specifies whether to denoise this render element.
The Reflection Filter Render Element is useful for changing the appearance of Reflective elements after rending, in a compositing or image editing software. In the example, the contrast of the Reflection Filter is increased, which makes reflective objects even more reflective. The Raw Reflection Render Element is used to colorize the reflections - the floor has a cool tint applied and the ceiling - a warm tint.
The Reflection Render Element is a product of VRayRawReflection x VrayReflectionFilter.