Wierd Fresnel Falloff Issue

[Druski]

Hi,

I've just noticed this happening when I use falloff maps in my diffuse slot using a fresnel falloff. This is a workflow I have never had problems with in the past, any ideas on whether the new build might be causing it. The problem only results when GI is used.

Drew

[bob-cat]

Hi Drew,

Not to sure what you mean, can you upload/email a scene with the map and I'll have a look?

[Druski]

Hey Bob-Cat,

Try rendering this scene using the the three materials in the material editor and you will see what I mean. I can't render using a falloff map in the diffuse slot of a material, I get crazy artifacts. Although when I use the falloff maps as a mix it renders fine.

Drew

[bob-cat]

Hi Drew,

The scene renders fine here. The same for both falloff materials, although I did change the mix colour to black to match the falloff map. I am using 1.5 final (not SP1), don't know whether that is the issue?

[Druski]

I've got a feeling the issue is with SP1. Thanks for testing it out for me.

Any ideas Vlado??

[RErender]

Looks ok here, just opened and rendered, SP1

[vlado]

Try checking the "Clamp" option in the Output section of the Falloff map and see if it helps.

Best regards,
Vlado

[Druski]

Her ReRender,

Was that render with only the falloff map in the diffuse or using the falloff as a mix?

Cheers,

Drew

[RErender]

Not sure, just downloaded your file and rendered it.

[Druski]

Hey ReRender,

Can you try this file for me. I had the wrong material applied in the other one.

[RErender]

This one looks ok too, what kind of cpu do you have? AMD? Both my tests where on different intels.

[Druski]

Here is how it renders on my machine, Intel Q6600, sounds like I've got something wierd going on from my end. Your definetly using SP1?

[RErender]

a crap, forgot we're still on 1.50.00 here at work... sorry for bad data

I'll try the new file when I get home on SP1

[RErender]

Yes, I get the bad render in SP1 but not 1.50.00, looks like a SP1 issue

[vlado]

This happens because of some calculation problems in the Falloff map when viewed at grazing angles; in SP1, certain code in V-Ray changed which made these problems apparent (although in theory they could still happen before as well). Turning on the Clamp option for the falloff map usually works fine. Otherwise, you can email me to vlado@chaosgroup.com for the fix.

Best regards,
Vlado