4 Main Things
1. Energy conservation. A reflected ray is never brighter
than the value it had when it first struck the surface.
Energy conservation is handled by the shader.
2. Fresnel. The BRDF is handled by the shader. The F0
reflectance value has minimal change for most common
dielectrics and falls within a range of 2-5%. The F0 for
metals is a high value, ranging from 70-100%.
3. Specular intensity is controlled through the BRDF,
roughness or glossiness map and the F0 reflectance
value.
4. Lighting calculations are computed in linear space.
All maps that have gamma-encoded values such as base
color or diffuse are usually converted by the shader to
linear, but you may have to ensure that the conversion
is properly handled by checking the appropriate option
when importing the image in your game engine or
renderer. Maps that describe surface attributes such as
roughness, glossiness, metallic and height should be set
to be interpreted as linear
OVERVIEW:
In PBR, the shader handles the heavy lifting of the rules of
physics through energy conservation and BRDF while, as artists,
we create maps that are guided by physical principles.
BRDF: Bidirectional Reflectance Distribution Function - A four-dimensional function that defines how light is reflected at an opaque surface and is a function of illumination geometry and viewing geometry.
SOURCE:
https://www.igi-global.com/dictionary/color-acquisition-management-rendering-and-assessment-in-3d-reality-based-models-construction/48698#:~:text=Definition%20of%20Bidirectional%20Reflectance%20Distribution%20Function%20%28BRDF%29%3A%20A,a%20function%20of%20illumination%20geometry%20and%20viewing%20geometry.
https://academy.substance3d.com/courses/the-pbr-guide-part-1 , McDermott, Wes, PBR Guide
1. Energy conservation. A reflected ray is never brighter
than the value it had when it first struck the surface.
Energy conservation is handled by the shader.
2. Fresnel. The BRDF is handled by the shader. The F0
reflectance value has minimal change for most common
dielectrics and falls within a range of 2-5%. The F0 for
metals is a high value, ranging from 70-100%.
3. Specular intensity is controlled through the BRDF,
roughness or glossiness map and the F0 reflectance
value.
4. Lighting calculations are computed in linear space.
All maps that have gamma-encoded values such as base
color or diffuse are usually converted by the shader to
linear, but you may have to ensure that the conversion
is properly handled by checking the appropriate option
when importing the image in your game engine or
renderer. Maps that describe surface attributes such as
roughness, glossiness, metallic and height should be set
to be interpreted as linear
OVERVIEW:
In PBR, the shader handles the heavy lifting of the rules of
physics through energy conservation and BRDF while, as artists,
we create maps that are guided by physical principles.
BRDF: Bidirectional Reflectance Distribution Function - A four-dimensional function that defines how light is reflected at an opaque surface and is a function of illumination geometry and viewing geometry.
SOURCE:
https://www.igi-global.com/dictionary/color-acquisition-management-rendering-and-assessment-in-3d-reality-based-models-construction/48698#:~:text=Definition%20of%20Bidirectional%20Reflectance%20Distribution%20Function%20%28BRDF%29%3A%20A,a%20function%20of%20illumination%20geometry%20and%20viewing%20geometry.
https://academy.substance3d.com/courses/the-pbr-guide-part-1 , McDermott, Wes, PBR Guide
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