Falloff Map

The Falloff Map node generates a gradient based on viewing angle. It can be used as a mask to blend between 2 textures or materials using a mix node.

Falloff Map Parameters

Mode - The Falloff Map mode:

• Normal vs. Eye Ray - The falloff is calculated from the angle between the surface normal and the eye ray. This mode is often used for reflections. The Falloff color range affects faces directly in front of the view, and gradually falls at angled faces towards the sides as it falls away from the straight-on viewing angle. The Direction parameter does not apply.
• Normal vs. Vector 90deg: The falloff is calculated from the angle between the surface normal and the specified direction vector maxing out at 90 degrees. This is similar to the default mode except that it maintains the effect of the color range according to the Falloff Direction.
• Normal vs. Vector 180deg: The falloff is calculated from the angle between the surface normal and the specified direction vector maxing out at 180 degrees. This provides a wider color range from the minimum to the maximum values, and maintains the effect of the color range according to the Falloff Direction.

Minimum Value - This is the value output at Normal angles facing the camera.

Maximum Value - This is the value output at Grazing angles facing away from the camera.

Falloff Skew Factor - Balances the Normal and Grazing angle influence. If set to 1, then the value is proportional to the angle between the Normal and the Camera Ray. For example, a value of 0.5 is equal to 45°. A value of 0.1 leads to almost complete coverage by the grazing value, while a value of 15 leads to almost complete coverage by the Normal value.

• falloff ≤ 1 : y = x falloff
• falloff ≥ 1 : y = 1 – (1 – x) (1 / falloff)

Direction - The falloff direction vector used by the Normal vs. Vector 90deg and Normal vs. Vector 180deg modes. Changing the object rotation will not change the Falloff Direction orientation.

NOTE: You can approximate the behavior of glass with a Skew Factor of 8.0 and a Minimum value of 0.034.