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Showing posts from July, 2020
GGX vs Blinn
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Image Source: https://academy.substance3d.com/courses/the-pbr-guide-part-1, PBR Guide, McDermott, Wes GGX most modern and flexible BRDF (Bidirectional reflectance distribution function) type and is able to better represent a broad range of materials thanks to its ability to control the shape of the specular lobe. Blinn is good for metallic surfaces with soft highlights, such as brass or aluminum. Because Blinn is a versatile material type and generally renders without problems, it's the primary material type we've used in these tutorials. SOURCE: https://academy.substance3d.com/courses/the-pbr-guide-part-1 https://www.peachpit.com/articles/article.aspx?p=31330&seqNum=3#:~:text=Blinn%20is%20good%20for%20metallic%20surfaces%20with%20soft,primary%20material%20type%20we%27ve%20used%20in%20these%20tutorials.
Specular Map
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Specular mapping is a method used to define the shape of shiny or reflective areas on a surface. For example, if a textured surface represents a wooden box with metal parts, a specular map can be applied to define only the metallic portions of the texture as shiny. SOURCE: https://community.secondlife.com/knowledgebase/english/materials-normal-and-specular-mapping-r1352/
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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: I...