This page offers information on the Shadow Select types of the Light Select Render Element in V-Ray for 3ds Max.
Overview
The Light Select Render Element represents the lighting contribution from one or more user-selected lights in the scene. The shadow modes - Direct diffuse shadow and Direct specular shadow - render a color image that works as a reverse mask for shadows caused by a specific light(s). It can lighten, darken, or tint the shadows in post-production.
The example scene here has three lights only - red, blue, and green to show compositing use cases for the Shadow select options.
Direct Diffuse Shadows
The Direct Diffuse Shadows channel outputs only the shadows cast by objects illuminated by pre-selected lights. This option has the same output as the VRayShadows render element. It works with all V-Ray materials that have diffuse (which excludes VRayStochasticFlakesMtl and VRayFlakesMtl2).
The V-Ray Toon material is not supported.
Example: Direct Diffuse Shadow
For this example, we render three Direct Diffuse Shadow channels - one for the green light, one for the red light, and another for the blue light.
Direct Diffuse Shadow Green Light
Direct Diffuse Shadow Red Light
Direct Diffuse Shadow Blue Light
RGB Color
Direct Specular Shadows
The Direct Specular Shadows channel outputs the specular information from the shadows cast by objects illuminated by a pre-selected light. For this channel to be visible, the objects onto which the shadows are cast must have reflective material. The channel works with all V-Ray materials that have reflection and glossiness values less than 1.
The V-Ray Toon material is not supported.
Example: Direct Specular Shadow
For this example, we render three Direct Specular Shadow channels - one for the green light, one for the red light, and another for the blue light.
Direct Specular Shadow red light
Direct Specular Shadow green light
Direct Specular Shadow blue light
RGB color
Compositing Example: Color Correction
For this example, the following color-correcting steps are done:
- First, switch the source to Composite.
- Then, add a new render element layer and leave it to RGB color.
- Add a new render element layer and rename it to Direct_Diffuse_Shadow_Red. Change the Blending to Subtract.
- Add a new render element layer and rename it to Direct_Diffuse_Shadow_Red. Change its Blending to Add. Tweak this layer using color corrections to achieve the desired look. Here, exposure and colors (with a Bezier curve) are tweaked.
- Do the same for the Direct Specular Shadow. For ease of use, sort them in folders.
RGB color
Direct Diffuse Shadow red light
Direct Specular Shadow red light
Composite result
Compositing Equation
For this compositing example, we render an RGB color and Shadow Select (both Direct Diffuse and Direct Specular Shadow types) render elements. Then, we subtract Shadow Select from RGB in compositing, grade the Shadow Select, and add it back to the composite.
