Glass

Glass simulates all glass and transparent surfaces that use physical refraction of light. Glass materials are materials that transmit light and at the same time refract it. To create such materials, it is not enough to use the Transparency parameter. Glass materials have 3 texture maps: Albedo, Normal, Roughness.

To create objects that look like glass, you may need to set the additional parameters: IOR, Absorbtion, Ambient, Turbidity and Aberation.

IOR (Index of Refraction)

IOR is a physical quantity. It controls the degree of light refraction, the permeability through the surface of the material, and also how well the reflections are visible on materials. If we increase the IOR (dragging the slider to the right), then we will see that the objects that are behind the glass begin to refract.

To create a more accurate imitation of the glass-like material, take the value from the IOR list for common materials. For example, the standard value for refraction of glass = 1.33.

Absorbtion

Transparent materials can absorb light into themselves, this is due to inhomogeneities and impurities that are inside transparent materials. If the value of Absorption is 100%, the object actually becomes opaque.

Ambient

Ambient is responsible for the intensity of the Reflection of the sun on glass materials.

Turbidity

Turbidity is responsible for the internal heterogeneity and clarity of the material.

Let's say we need to create a glass ball from unevenly cooled glass. This ball will consist of several glass layers with an inhomogeneous structure. Light is also reflected inside each layer of glass. This reflection also follows the laws of refraction and reflection inside this glass ball. As a result, refraction of light and turbidity begin to occur inside this object, which also affects the transparency/opacity of the object itself.

This parameter is used to create a thick piece of glass, crystal, quartz, inside which you need to show multiple re-reflections. You can also use this parameter to create ice. Ice never occurs simultaneously. Ice looks like a monolith from the outside, but inside it is heterogeneous. Turbidity will help to create this heterogeneity.

Aberations

To make your glass object even more realistic, you can use the Aberation parameter. By increasing this parameter, a clear rainbow effect will appear on the glass object.

In the physical world, this effect can be seen on the surface of transparent materials in the form of narrow colored stripes in the vertical direction (for example, on double-glazed windows, on a puddle with drops of gasoline, on pieces of ice).