fresnel bug??

[dominiquelaksmana]

couldnt you just use a falloff map in the reflection slot ?

Yes, that's another option, which might also do it.
Actually that is even simplier. Thanks.

Best regards,
nikki Candelero

the same thing will happen.
[img][/img]

[studioDIM]

I think you should try and go Vlado's way (duh, that was a smart bet...): lower the cutoff, which will insure even the fainter reflections will be picked up, and then readjust the material ior.
If you use a falloff map, make sure you are adjusting the proper ior depending on the "override ior" checkbox state, and try and play with the output curve so to have a finer controll of the falloff.

In any case, if the problem indeed sits with the cutoff, the same material with a different falloff type (towards/away, for example) should exhibit the same issue at the reflection fringe.

Lele

[Morbid Angel]

you may also try fall off map, I find that gives you much more control over the falloff curve.

[teabag]

thats correct...i am always using fall off map, but if you use fresnel option in the falloff map you should be careful about mode specific parameters, there is a tick -override material IOR- i think it needs to be ticked and you specify the fresnel IOR there, if unticked you would be applying fresnel twice i suppose...anyway using fall off map with fresnel option can sometimes cause splotches

[Morbid Angel]

if you use a falloff map in reflection slot, then uncheck fresnel option in vray mat...
and then do your magic from falloff map only.

[dominiquelaksmana]

falloffs reflection maps doesnt help. because vray fresnel took the "falloff" from there also.. please try this and you will feel frustrated also.

[Sushidelic]

Hi,

I really don't understand what this is all about... Just follow Vlado's suggestion and set the reflection/refraction cutoff to 0.0 - the default of 0.01 is in many situations way to high imho. If ticking fresnel and adjusting the ior isn't flexible enough for you, just go ahead and use a custom falloff in the reflection slot and adjust it to your needs.

so. i know it's a small problem, probably, someone would say,
dont use lwf then, or don't use reflection under the value of 50...


but then also this is not visible when you are not using wide angle camera, since my client is a wide angle camera freak, so i am getting this effect on my floor. very sharp line between the reflective and not reflective area..

any advise my good fellas??
thanks

Once again: This problem is ONLY related to the cutoff treshold - if you set it to 0 even faint reflections are computed and the result is the correct reflection including the fresnel effect! So this post should rather belong to the tutorials, tips and tricks section than to bug reports

my 2 cents,
Michael

[dominiquelaksmana]

my apologies if i ticked anybody off...
anyway thanks for the tips guys....

[RErender]

I don't think any one is ticked off, I just think we do not really understand what you are looking for. It seems to be working correctly If you want the reflections to fall off quicker, lower the ior. Maybe find some photo ref for what you want to do and we can see if it is doable.

[Morbid Angel]

Im pissed off as hell !!!!

[re:FORM]

Bringing this thread back from the dead... I think I've got a problem relating to the reflect-refract-cutoff problem....

check out the render :-



The material is a straight white reflection with fresnel falloff (I've tried both fresnel checkbox, and falloff map). The circle is related to the bump map I'm using. In the bumpmap slot I have:-

Mix map
slot-1 = black
slot-2 = Noise map (the ripples in the render)
mixmap = gradient (black to white, mid point 0.5)

Why do I loose the gentle falloff on the bumpmap? Whats weird is that if I stick that mixmap in the diffuse slot, the map renders how I would expect it to look, ie black edge with slight ripples towards the middle of the panels. Its only when I have this map in the bump slot, then switch on reflections that this harsh defined circle appears.

I've tried reducing the reflect refract cutoff to 0.0001 (the lowest it would let me). I've also tried using the vray colour map in the gradient map to ensure its using float values for the gradient.

The glass was built using planes with the shell modifier to give them thickness.

Any ideas?

[re:FORM]

<edit> mistaken post

[dlparisi]

The gradient's not going to give you the bump you're looking for. I tried a similar route and couldn't really get it to work like I wanted to for two reasons: 1 - the ramp is linear (or even eased) so it doesn't really approximated that curved/bowed glass I think your looking for and 2 - you'll need to change the tiling options to something below 1 to make the radial gradient cover more of the face to avoid the black corners. To avoid all of this I made a simple plane with just a few control points and pulled the center ones up to give me a nice gently curving plane (add a mesh smooth too). Render out a z depth pass from above or just apply a self illuminated ramp to it from the bottom to the top so you don't need to worry about proper depths.

I usually just put this map and a noise map into the two slots of an RGB Multiply map to get the bump I need but the mixMap would probably work too.

[dlparisi]

Here's the bump map I use...


This is a JPG copy of the TIF that I normally use because I was worried about banding in the gradient. You may want to still generate you own or if you PM me I can send you the TIF.

David

[re:FORM]

Hah, thanks dlparisi... I was just building my own as you sent that...

I notice the edges aren't black.... does this not cause a problem with the edges appearing to lift?