Thin Film

The Thin Film Appearance Type simulates items such as soap bubbles and oil slicks, with rainbow color distortion on the surface layer.

Parameters

Color Sets the base color of the appearance. Transparency is supported.
IOR (Index of Refraction) Sets the appearance's reflectivity and distortion of light penetrating it.
Film IOR Changes the surface layer's IOR separately from the base. This affects the surface layer color.
Film Thickness (µm) Sets the overall appearance thickness. Very thin films are mostly surface layer, which tends to have strong visual effects. Thicker films take on more of the base appearance's properties, with less effect from the surface layer.
Film Thickness Randomness Indicates the amount of variation to the film interference. Low randomness reveals less interference between the wavelengths of light passing through the film thickness resulting in less color shift where high randomness exaggerates interference and generates more color and pattern shifts.
Roughness Controls the highlight size in reflected light. The rougher the appearance, the more it diffuses the highlight (the larger and less focused the highlight becomes).