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Fresnel Reflections on Transparent Glass


martin walker
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The thing with fresnel reflections is that it is almost giving the glass the reflection vray thinks it should have. Perhaps I'm incorrect, but I don't use fresnel reflections on glass. That way I can be the one telling it how much to reflect. The best thing to do is search for images that have a similar glass, similar light settings (exterior), and a similar angle on the glass. then try to match that. Different glass reflects and refracts differently. To me, fresnal reflections are better for small non-architectural glass like a mug, or something.

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The thing with fresnel reflections is that it is almost giving the glass the reflection vray thinks it should have. Perhaps I'm incorrect, but I don't use fresnel reflections on glass. That way I can be the one telling it how much to reflect. The best thing to do is search for images that have a similar glass, similar light settings (exterior), and a similar angle on the glass. then try to match that. Different glass reflects and refracts differently. To me, fresnal reflections are better for small non-architectural glass like a mug, or something.

 

thanks Tim....your thinking is the same as mine...I just thought I was doing something wrong !!!

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Everything in nature has a fresnel falloff in the reflection just like everything in nature is effected by gravity. The issue with the fresnel check in vray is that it does not account for the face forward reflection. Instead of using the fresnel checkbox, use a falloff map in fresnel mode and make the forward face slightly brigter than black. That should give you want you want.

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Christropher. It is not working. I am having the same problem with respect to reflections and refractions. I have an interior scene with glass in window. The window has vray mtl with refraction=100. No map. If i place any object behind it (outside window), it shows it in rendering but it doesnt show me the envioronment in which i am using HDRI.

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Try not having your refraction at 100%. It would be hard to see reflections on a 100% transparent object. Fall off map- bottom slot all white, top slot brighter than full black (u determine amount) is the wat to go.

 

Could also try to brighten the material that is being reflected so it is easier to see/pick up.

 

Good luck.

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What I have started doing is putting a fresnel falloff in the reflect slot and putting the reflect color swatch to white. Then I can reduce the fresnel effect of the map I can tweak the reflection a bit.

 

Thanks Sawyer, Ive had a play with this method and got just the result I was after...I owe you a beer ;)

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  • 3 years later...

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