use of IOR parameter of " refraction " on opaque objects?

[chow choppe]

hi everyone.

recently while going through a tutorial i noticed that in creating a wet mud material glossy reflection was added to it and then fresnel was turned on.

also in refraction parameter IOR was increased to 6.0

is this the refraction IOR or it affects the reflections?

i am confused. or IOR affects both reflections and refractions?

 

for a transparent material i understand this value affecting bending of light but for an opaque material how does this effect the material?

 

please advise

 

Thanks

[Karrde]

IOR affects both reflection and refraction. You can however untick the little "L" icon beside the fresnel checkbox and control IOR for them separately.

[chow choppe]

so instead of increasing fresnel reflection IOR value by unticking that L ,the guy must have increased the fresnel reflection by just changing the plain IOR value in the refraction slot. right?

which means until the material is transparent it will just affect the reflectivity of the object and once it becomes transparent it will also start affecting the refraction ?

Edited July 28, 2011 by 3dsmaxed

[Karrde]

Exactly. There is no point in setting IOR individually to relfection if the material is opaque, so you just use the general one.