Vray Fresnel reflection weirdness

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Old 03 March 2013   #1
Vray Fresnel reflection weirdness

Lately I've been trying to get some subtle reflection around the edge of the object. But no matter how I try, once I lower the IOR or lower the reflection amount, there is always some sharp cut off happening. The effect is not very noticeable in linear space... but as soon as I turn on sRGB, well...

Here's a simple sphere. Vray Mtl, black diffuse, white reflection, pure white reflection over-ride. Fresnel IOR 1.1. Left is linear without color correction, right is with sRGB applied.



Here's the same scene, replacing the white reflection over-ride with an HDR



Any advise how I to deal with this? I tried connecting ramps with sampler info myself but the result is still the same.

Thanks.
Attached Images
File Type: jpg srgb1.jpg (10.3 KB, 120 views)
File Type: jpg srgb2.jpg (15.8 KB, 115 views)
 
Old 03 March 2013   #2
You need to turn the reflection cut off threshold down to 0.01 or something like that -its in the vray mtl settings. I end up doing this on most of my very glossy materials
 
Old 03 March 2013   #3
Ahh Thanks terminvox! The label only says Cutoff threshold, wouldn't have thought it's for reflection.

 
Old 03 March 2013   #4
Originally Posted by terminvox: You need to turn the reflection cut off threshold down to 0.01 or something like that -its in the vray mtl settings. I end up doing this on most of my very glossy materials


0.01 is the default.
 
Old 03 March 2013   #5
Originally Posted by cgbeige: 0.01 is the default.

Apparently. I had to lower it to 0.001, or in extreme case, 0
 
Old 03 March 2013   #6
Oops. Beige is right -but I guess it was obvious what I meant.
You probably know about this but some really nice tips for vray materials here..

http://bertrand-benoit.com/blog/201.../materialism-1/
 
Old 03 March 2013   #7
thanks - that looks great.
 
Old 03 March 2013   #8
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