martin walker Posted November 21, 2006 Share Posted November 21, 2006 I dont seem to have any luck when using Fresnel Reflections in a vray material...especially in an external glass scenario. As soon as I switch it on I get almost no reflections and a dark looking material...any suggestions ? material settings attached Link to comment Share on other sites More sharing options...
martin walker Posted November 21, 2006 Author Share Posted November 21, 2006 Heres a screen shot to show what Im getting Link to comment Share on other sites More sharing options...
Trevor Tizard Posted November 21, 2006 Share Posted November 21, 2006 If you increase the Fresnel IOR value from 1.6 the reflections will be brighter Link to comment Share on other sites More sharing options...
AJLynn Posted November 21, 2006 Share Posted November 21, 2006 What's it reflecting? Do you have an environment for it to reflect? Link to comment Share on other sites More sharing options...
martin walker Posted November 21, 2006 Author Share Posted November 21, 2006 yes, theres a sky box in...you can see it on the screen shot. I get really nice results with Fresnel reflections on shiny stuff...cars etc...nice glancing / fall off reflections, but for some reason cant get a decent result with glass Link to comment Share on other sites More sharing options...
AJLynn Posted November 21, 2006 Share Posted November 21, 2006 I think the render is accurate - you're looking at it almost straight on, and Fresnel will give it a low reflectivity at that angle. If you want it more reflective, like Trevor said, you can increase the Fresnel IOR. Link to comment Share on other sites More sharing options...
Tim Saunders Posted November 21, 2006 Share Posted November 21, 2006 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. Link to comment Share on other sites More sharing options...
Sawyer Posted November 21, 2006 Share Posted November 21, 2006 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. Link to comment Share on other sites More sharing options...
martin walker Posted November 21, 2006 Author Share Posted November 21, 2006 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 !!! Link to comment Share on other sites More sharing options...
Christopher Nichols Posted November 22, 2006 Share Posted November 22, 2006 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. Link to comment Share on other sites More sharing options...
aligrafix Posted November 22, 2006 Share Posted November 22, 2006 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. Link to comment Share on other sites More sharing options...
Tim Saunders Posted November 22, 2006 Share Posted November 22, 2006 It sounds to me like you guys are having problems unrelated to the fresnel/falloff technique Chris mentioned. I have used the method many times and it worked just fine. Keep in mind, that technique should be used in the reflection slot. That doesn't effect your refraction. Link to comment Share on other sites More sharing options...
mr. a Posted November 27, 2006 Share Posted November 27, 2006 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. Link to comment Share on other sites More sharing options...
martin walker Posted November 27, 2006 Author Share Posted November 27, 2006 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 Link to comment Share on other sites More sharing options...
bluejacky Posted November 26, 2010 Share Posted November 26, 2010 have same issue. increasing the frensnel IOR really help. Thanks. Link to comment Share on other sites More sharing options...
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