This page gives some basic details about the Shadow Render Element and how it is used in compositing.
||Render Settings window|| > Render Elements tab > Shadow
The parameters for this render element appear in the Attribute Editor under Extra V-Ray Attributes.
Enabled – 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.
Filename suffix – The text added to the end of the rendered file, when saved as a separate file (e.g. myrender.shadow.vrimg).
Apply color mapping – Applies the color mapping options specified in the Color mapping rollout of the VRay tab in the Render Settings window to this render element. This option is enabled by default.
Denoise – Enables the render element's denoising, provided the Denoiser render element is present.
The Shadow Render Element is useful for changing the appearance of shadowed areas in a compositing or image editing application. Below are examples of possible uses.
vrayRE_Raw_Shadow x vrayRE_Diffuse = vrayRE_Shadow