mapping vrayMtl refraction ior with falloff texture

[Armin Mueller]

Hello,
I am trying to map the refraction ior of a vrayMtl with a falloff texture.
I set the falloff texture front color value to 1.1 and the side color to 1.33
and plugged that directly in the ior slot. (probably naive
I tried the various falloff modes but I get no usable results.
I also tried to use a RGB to luminance between the falloff tex and the ior,
but this does not cut it either.
So I guess it is more complicated than that.
I would like to have the object (waterlike bubble) refract stronger
on the sides and weaker on the front.
Blending two materials with different ior's with a falloff texture
renders a lot longer and feels somehow hacky.

Appreciate any ideas on this.

Armin

[Morbid Angel]

This should work, does your bubble geometry have thickness?

[Armin Mueller]

No it doesn't, it's solid. It's a subdivided cube, deformed and animated with a lattice and a texture deformer.

[Morbid Angel]

you need thickness in geometry otherwise it will not produce correct refraction.

[Armin Mueller]

Thanks for your help. Is it not possible to map the ior of
a solid object i.e. a water bubble floating in zero gravity?