problem with minimum reflection cutoff?

[galakgorr]

hello,

i have been working on a material with a fairly low amount of reflectivity. my problem is that if my IOR is low enough (around 1.4 or so) and the reflected color value of the shader is low enough, a big gaping hole opens up in the environmental reflection. i'm using linear workflow, reinhard color mapping. this is vray 1.5sp1 for maya 2011.

i attached the two examples. there is an hdri environment providing the reflections. the reflection color of the material with the hole is 0.191, fresnel is ON, and the reflection IOR is 1.5. in the reflection pass, the color value (i'm rendering to full float) is zero in the "hole."

i imagine there must be some sort of minimum cutoff value? if i brighten up the reflection color or turn up the IOR a bit, the hole will close up a little. raising the IOR or the reflection color enough will close it entirely. how can i prevent this hole from happening?

[snivlem]

Try lowering the cutoff threshold under the material (it is under the Options tab in the material)

[galakgorr]

thanks! that's exactly what i was looking for.