A material with the Glass BSDF can produce realistic results with

advanced transparency (Figure 5.23).

Figure 5.23 - Glass BSDF (Cycles)

Use the IOR settings to control how the light diverts from your model's

interior using a material with a Glass BSDF. You can also mix shaders to

achieve unique effects using transparency.

5.6 Glossy surfaces

If you want a surface with a certain level of reflection, you must use

either a Glossy BSDF or the Principled BSDF. Both shaders feature

settings that control how your material will reflect light: roughness.

A material that has a roughness close to zero has a perfect reflection,

almost like a mirror. For higher values, it starts to get a blurred reflection

until you can't identify the objects reflected anymore (Figure 5.24).