OTOY Forums

I have read the manual buy still I am a little bit confused about the "index" value to input when I have to create metal materials.

Observing the materials stored on the DataBase seems that the correct procedure must be:
- set 1.0 in the "index" field,
- set 1.0 and generally a black color in the "specular" field,
- generally set 0 and black color in the "diffuse" field,
- work around the correct value of "roughness" finding the desidered aspect of the material.

Is the correct procedure?

In that case, when is useful to use the phisically correct IOR value?
For example:
If I want to create an Aluminium material, I should input an IOR of 1.44, but in this case I'll can't reach the correct aspect of the material (almost for my test and -limited- experience).
Thanks to all.

Luca

I assume the index value works as it does in any other 3d soft. Follow the these IOR tables you are taking your data from as a general guide. Ultimaetly - measure with your eyes, design is visual. If an IOR value does not give the look you are after - alter it. Dont look for a set in stone rule here.

GIOLETS wrote:I have read the manual buy still I am a little bit confused about the "index" value to input when I have to create metal materials.

Observing the materials stored on the DataBase seems that the correct procedure must be:
- set 1.0 in the "index" field,
- set 1.0 and generally a black color in the "specular" field,
- generally set 0 and black color in the "diffuse" field,
- work around the correct value of "roughness" finding the desidered aspect of the material.

Is the correct procedure?

In that case, when is useful to use the phisically correct IOR value?
For example:
If I want to create an Aluminium material, I should input an IOR of 1.44, but in this case I'll can't reach the correct aspect of the material (almost for my test and -limited- experience).
Thanks to all.

Luca

yeah the 0 is right way. octane doesn't have the "K" value fully implemented yet, which you need to correctly use IOR numbers for opaque materials. Setting the IOR to 0 effectively removes falloff altogether, which if you look at reflectivity values of metal, you'll notice that they are pretty much reflecting the same amount of light straight on as they do at glancing angles.

I start with a 0 value and if the metal is too bright, too reflective, i'll go the opposite direction and just put a high index value till it looks correct.

Until they get the K value added in, don't worry about what index number you're using on metals, just do what looks correct to your eye.