The Base Color defines the main color of the Stencil Lights or Shadows effect.

Each Blend Mode will use the Base Color differently, but you can generally expect the final color to be a lightening or a darkening effect tinted with the Base Color. The alpha channel is ignored, except for some advanced blending modes under “Alpha Blending”. The intensity of the effect is usually set by the brightness of the Base Color.

Enable this option to use the vertex color of each rendered mesh as the base color for the effect.

For performance, we suggest using the least number of materials in your scene. If you have several different colors, performance can be improved by using the vertex color option and encoding the color information in the mesh, so you can have a single material rendering all stencil effects in your scene.

“Show Volume” enables rendering of the volume of the mesh in addition to the main effect. The rendered volume always uses the same blend mode as the main effect,

You can customize the color that is used as the base color for the volume rendering. Enable “Advanced Volume Color” for more option on how to control the color of the volume effect.

“Strength” controls the intensity of the volume color in comparison to the Base color.

Blend modes affect how the final color of the effect will be rendered. There are two basic blend modes, which were designed to be simple to use:

Both “Light” and “Shadow” blend modes are commutative, which means that when stacked on top of themselves the result is independent of rendering order, resulting in no z-fighting. This property is not true for some of the advanced blend modes, as noted below.

There are sixteen advanced blend modes, divided into six different categories.

*Difference is slightly different from the conventional Difference blend mode found in traditional image editing software. It does NOT take the absolute value of the difference. As a result, this blending mode is non-commutative, which differs from the conventional implementation.

Formulas are described using the following notation:

• Result = the final RGB color that will be rendered
• Base = the RGB of the Base Color of the Stencil Lights and Shadows
• Alpha = the alpha channel of the Base Color of the Stencil Lights and Shadows
• Background = the RGB color of the background behind the Stencil Lights and Shadows
• 1 = (1,1,1) = White
• 0 = (0,0,0) = Black

Colors cannot have values below zero or above one (they will be clamped accordingly). Divisions by zero result in undetermined behavior and should be avoided.

Color channels (R, G, B) are calculated independently to produce the result color. The blend mode specified applies both to the main effect of Stencil Lights and Shadows and to the effect rendered by the “Show Volume” option.

Blend modes that are non-commutative require more caution when used.

When overlapping two meshes with the same blending mode that in non-commutative, the result will be dependent on draw order. This can result in image artifacts “popping in and out” and z-fighting, which is often undesirable.

To mitigate this, you can either:

• Ensure that no Stencil Lights and Shadows overlap.
• Or use different materials for each Stencil Lights and Shadows, each with a distinct Render Queue value (this can be done in the Material Inspector itself)