realistic spec... or something...

ok this is seriously burning my brain and i cant find the answers im looking for anywhere. I not only want to know what this is and is really called, but id also like to know how to do it in blender.
what causes the reflections on the eye to vary by light intensity? the white light of the sky is the only thing that has an effect on the eye, as far as obscuring our view of the true color. the places that are getting low light reflection are not really reflecting anything at all… like zero alpha. so how does this work and how do we fake it?

man, hope someone’s got an answer… my head might just explode over this :slight_smile:

It does not vary by light intensity. It varies by incidence angle. This is called fresnel effect.

And all transparenct reflective materials are both at the same time. How much a material is see through depends on the amount of light that is reflected by it. And it’s not difficult to achieve that effect, Blender does that automatically with raytraced reflections.

fresnel, is not what im talking about. and maybe you do know what i mean, but ill use the fresnel to illustrate better…

where it shows the shpere in the checkerboard corner: what im looking for is the ability to make the reflection of the black color disapear. as if the white checks were emitting light and the blacks were nothing. as in the frog eye, if this effect did not exist, then the colors of the photographer and the trees would mask the blackness of the pupil, as the black/non light emitting checks mask the grey of the sphere, but they do not… obviously fresnel takes place in this situation, but it is not what my question is focused on.

As you can see (though it may not be a perfect example) is the amount of see-through-ness totally dependent from the colour and amount of light of the surrounding. The outer sphere has no fresnel, only simple raytracing reflections and transparency.