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#Actuallipsryme

Posted 03 November 2012 - 04:30 PM

I've got a few questions that I'd love to get some insight on.

1. When using a normalized brdf how do you tweak(?) the intensity of the specular highlight. Isn't the point of this to get a result which is <= 1 ?
Which also brings up another question. Considering the normalization factor for a phong brdf: (SpecularPower + 2) / (2 * PI) and not using any geometry or fresnel term the specular would always be 'blazingly' bright (and a lot higher than 1). Also wouldn't multiplying the result with some value aka specular intensity value afterwards distort from the original idea of normalizing it ? If that's true how do you control the intensity of this specular ?

2. When trying to make a metallic looking material, how would you create the diffuse and specular map for it considering its real life behavior. You can't just use a black diffuse map and only use a specular to make the entire object lit can you ? At least it didn't work for me. Wouldn't the rest of the object be completely black (if no ambient term was there) ? Also this might be more of an artist's problem but if you'd use the fresnel reflectance color of a material F(0°) e.g. a stonewall which probably would have a very low color how would I create such a specular map without loosing detail. Because lowering the maximum brightness of this map to 0.02 (for example) makes it almost entirely black and all its details will be lost.

#6lipsryme

Posted 03 November 2012 - 01:24 PM

I've got a few questions that I'd love to get some insight on.

1. When using a normalized brdf how do you tweak(?) the intensity of the specular highlight. Isn't the point of this to get a result which is <= 1 ?
Which also brings up another question. Considering the normalization factor for a phong brdf: (SpecularPower + 2) / (2 * PI) and not using any geometry or fresnel term the specular would always be 'blazingly' bright (and a lot higher than 1). Also wouldn't multiplying the result with some value aka specular intensity value afterwards distort from the original idea of normalizing it ? If that's true how do you control the power of this specular ?

2. When trying to make a metallic looking material, how would you create the diffuse and specular map for it considering its real life behavior. You can't just use a black diffuse map and only use a specular to make the entire object lit can you ? At least it didn't work for me. Wouldn't the rest of the object be completely black (if no ambient term was there) ? Also this might be more of an artist's problem but if you'd use the fresnel reflectance color of a material F(0°) e.g. a stonewall which probably would have a very low color how would I create such a specular map without loosing detail. Because lowering the maximum brightness of this map to 0.02 (for example) makes it almost entirely black and all its details will be lost.

#5lipsryme

Posted 03 November 2012 - 01:04 PM

I've got a few questions that I'd love to get some insight on.

1. When using a normalized brdf how do you tweak(?) the intensity of the specular highlight. Isn't the point of this to get a result which is <= 1 ?
Which also brings up another question. Considering the normalization factor for a phong brdf: (SpecularPower + 2) / (2 * PI) and not using any geometry or fresnel term the specular would always be 'blazingly' bright (and a lot higher than 1). At least for most exponents. Also wouldn't multiplying the result with some value aka specular intensity value afterwards distort from the original idea of normalizing it ? If that's true how do you control the power of this specular ?

2. When trying to make a metallic looking material, how would you create the diffuse and specular map for it considering its real life behavior. You can't just use a black diffuse map and only use a specular to make the entire object lit can you ? At least it didn't work for me. Wouldn't the rest of the object be completely black (if no ambient term was there) ? Also this might be more of an artist's problem but if you'd use the fresnel reflectance color of a material F(0°) e.g. a stonewall which probably would have a very low color how would I create such a specular map without loosing detail. Because lowering the maximum brightness of this map to 0.02 (for example) makes it almost entirely black and all its details will be lost.

#4lipsryme

Posted 03 November 2012 - 01:03 PM

I've got a few questions that I'd love to get some insight on.

1. When using a normalized brdf how do you tweak(?) the intensity of the specular highlight. Isn't the point of this to get a result which is <= 1 ?
Which also brings up another question. Considering the normalization factor for a phong brdf: (SpecularPower + 2) / (2 * PI) and not using any geometry or fresnel term the specular would always be 'blazingly' bright (and a lot higher than 1). At least for most exponents. Also wouldn't multiplying the result with some value aka specular intensity value afterwards distort from the original idea of normalizing it ? If that's true how do you control the power of this specular ?

2. When trying to make a metallic looking material, how would you create the diffuse and specular map for it considering its real life behavior. You can't just use a black diffuse map and only use a specular to make the entire object lit can you ? At least it didn't work for me. Wouldn't the rest of the object be completely black (if no ambient term was there) ? Also this might be more of an artist's problem but if you'd use the fresnel reflectance color of a material F(0°) e.g. a stonewall which probably would have a very low color how would I create such a specular map without loosing detail. Because lowering the maximum brightness of this map to 0.02 (for example) makes it almost entirely black and all its details are also lost.

#3lipsryme

Posted 03 November 2012 - 01:02 PM

I've got a few questions that I'd love to get some insight on.

1. When using a normalized brdf how do you tweak(?) the intensity of the specular highlight. Isn't the point of this to get a result which is <= 1 ?
Which also brings up another question. Considering the normalization factor for a phong brdf: (SpecularPower + 2) / (2 * PI) and not using any geometry or fresnel term the specular would always be 'blazingly' bright (and a lot higher than 1). At least for most exponents. Wouldn't multiplying the result with some value aka specular intensity value afterwards distort from the original idea of normalizing it ? If that's true how do you control the power of this specular ?

2. When trying to make a metallic looking material, how would you create the diffuse and specular map for it considering its real life behavior. You can't just use a black diffuse map and only use a specular to make the entire object lit can you ? At least it didn't work for me. Wouldn't the rest of the object be completely black (if no ambient term was there) ? Also this might be more of an artist's problem but if you'd use the fresnel reflectance color of a material F(0°) e.g. a stonewall which probably would have a very low color how would I create such a specular map without loosing detail. Because lowering the maximum brightness of this map to 0.02 (for example) makes it almost entirely black and all its details are also lost.

#2lipsryme

Posted 03 November 2012 - 01:01 PM

I've got a few questions that I'd love to get some insight on.

1. When using a normalized brdf how do you tweak(?) the intensity of the specular highlight. Isn't the point of this to get a result which is <= 1 ?
Which also brings up another question. Considering the normalization factor for a phong brdf: (SpecularPower + 2) / (2 * PI) and not using any geometry or fresnel term the specular would always be 'blazingly' bright. At least for most exponents. Wouldn't multiplying the result with some value aka specular intensity value afterwards distort from the original idea of normalizing it ? If that's true how do you control the power of this specular ? Even without this external intensity value the result would be a lot higher than 1 would it not ?

2. When trying to make a metallic looking material, how would you create the diffuse and specular map for it considering its real life behavior. You can't just use a black diffuse map and only use a specular to make the entire object lit can you ? At least it didn't work for me. Wouldn't the rest of the object be completely black (if no ambient term was there) ? Also this might be more of an artist's problem but if you'd use the fresnel reflectance color of a material F(0°) e.g. a stonewall which probably would have a very low color how would I create such a specular map without loosing detail. Because lowering the maximum brightness of this map to 0.02 (for example) makes it almost entirely black and all its details are also lost.

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