Default for VRayMtl cutoffThreshold must be lower than 0.01

[ultrasonic]

Hey Guys,

we are just encountering issues with the cutoffThreshold when using Fresnel IORs below 1.33 for reflection. We found that we have to lower the cutoffThreshold to about 0.001 otherwise reflections just get clipped off. Since fresnel values below 1.3 are not really rare i suggest to change the default setting to avoid this problem. Would be very nice of you! Or does this affect preformance significantly?!?

cheers
Oliver

[vlado]

Changing the default might not be a good idea; it will slow down the renderings by default when I haven't really noticed issues with the default value, even with IOR 1.33. It would be good to get us the Maya scene to vraymaya@chaosgroup.com so that we can check if something else might be a problem.

Best regards,
Vlado

[3DMK]

We have exactly the same issue in Max with the default cutoff value as well!

http://www.chaosgroup.com/forums/vbulletin/showthread.php?48209-Problem-default-cutoff-value-[Reflections]-in-Vray-material-using-Falloff&p=419211#post419211

I can understand however that it may not be a good idea to change the default value as it only happens with certain material setups & most of the time works fine.
I guess it's a matter of knowing which reflection setups it will affect & making sure those materials are set to a lower cutoff.

[ultrasonic]

3DMK: yep...seems to be the same issue.

but i also have to say that this is not a real problem,since one can easily solve it by lowering the default cutoff by hand.