What's the difference between Glossy and Glass shaders in Eevee? What's the difference between Glossy and Glass shaders in Eevee? Also What's the difference between Glossy and Glass shaders and Roughness parameter in Princepled BSDF shader?
From left to right, is Glossy, Glass, and &quot;Shiny&quot;. All 3 have roughness at 0.

Roughness in Principled BSDF determines how &quot;shiny&quot; or &quot;polished&quot; the surface of somthing looks. It bears no effect on the underlying colors.
Glossy is the equivalent of metallic - the color determines the hue of the specular reflection (how much of its own color is reflected back with the light). Default (white) Glossy with roughness 0 is the equivalent of Pure Metal (White basecolor, Roughness = 0, Metallic = 1) on Principled BSDF.
Glass essentially a Glossy shader, but with a transparent BaseColor, and some refraction added which also gives transparent/refracted reflections. It also includes a Fresnel to alter the refractions near the &quot;edge&quot; of objects. It is one of the best ways of replicating glass in Cycles, but has its limitations in EEVEE.