architectural glass...how to improve?

[fabrizio]

This is my last work
but I'm not satisfied for the glass....



I have a spherical map in the environment slot but I can't see the sky reflected and the clouds.

1-is it better a glass with or without fresnel?
2-can hdri improve the quality of the realism of the glass? I download free hdri from some website but I can't achieve a good result....the hdri are too saturated.

thanx

[jow]

what are your material settings fabrizio?
ive always understood that glass should have fresnel ticked.

[TutanMark]

Ciao Fabrizio,

Better with fresnel, at least for me... but using a map instead of the simple on/off function.

U can control better the riflection using different reflection and refraction IORs.

Hdri are wonderfull too, just control them using multiplier. Of course is better if you buy some professional images.

On Devebec's site u can find great free images, but If u prefer to buy: Sachform and Dosch design.... just examples

Ps:
Hi Jow, did you solve that problem i showed some nights ago?... i didn't.. but i rendered a final image with still errors, corrected in photoshop.

Regards,
Marco

[fabrizio]

hi,
the glass is a simple glass...ior 1,55 for the glass, and 30 is the value of the reflections.
I tried with fresnel but I see some effect only for reflection ior > 2.

thanx

[flipside]

When using fresnel, you need to increase reflection strength a lot. For glass I would use reflection of near white (for example 230) and fresnell ior=1.6

The problem with this glass is that they are flat surfaces, so they reflect only a very small part of the 360° environment. You'll need high resolution environment maps to get decent results.

[fabrizio]

thanx a lot

fabrizio

[jow]

TutanMark worte,

Hi Jow, did you solve that problem i showed some nights ago?... i didn't.. but i rendered a final image with still errors, corrected in photoshop.

yes mate thanks,changing from photometrics to standard omni's fixed the problem also shaves abit of time of the render.
still got some issues with the lights not being bright enough,i need to tweak falloff settings.have a look see what you think;
http://www.chaosgroup.com/forum/phpB...ic.php?t=12366
still WIP, got a bit to do yet(fixed faceted drum and trip hazard!!)
cheers jow.

[zoranm]

Fabrizio,

My setup is similar to Flipside's. I also change the black colour swatch in falloff to 10-15. If you leave it on pure black that means that if you look at the glass perpendicilarly you almost wouldn't see any reflections. In real life is not like this so changing colour slightly to dark grey correct this.
Also try to increase the strenth of reflections of HDRI map to 1.2-1.5.


Hope this helps

Zoran

[fabrizio]

hi zoranm,

but did you use a falloff map in the reflection slot? or did you use only the fresnell effect builtin in vrayìmaterial (near the reflection slot)?


thanx

[flipside]

He used falloff map, because he's talking about the color swatches in that falloff map. I used to to that too, but now since you can set fresnel ior different than refraction ior, I always use the built in fresnell effect.

If you want stronger reflections in the perpendicular area, use a higher fresnell ior. The higher you go, the less the fresnell effect will be visible.

[fabrizio]

thanx flipside.

BTW. vray is phisical correct....is it true?....so what is the right ior for the fresnel effect of the glass? I suppose there is a table withe the correct reflect ior like refract ior.


bye

[flipside]

If you want it to be correct, you should leave the fresnell ior linked to the refraction ior

[fabrizio]

thank you very much

[zoranm]

HI Fabrizio

Sorry for the confusion. I was definatelly talking about Standard material with reflection maps. I still prefer to use reflection map than Vray material for glass:
1. I often get from architects half-backed models with single planes for glass
1a. It's one of my Standard Library Materials.
2. Using falloff in reflection slot (Standard material) gives me more control of the fresnell effect. I can fine tune it by adjusting the Mix Curve. This is not phisically correct as Fresnel in Vray material. Flipside is right in saying that you can do the same thing by increasing IOR but that basically means that your reflections are becoming more "metalic". For this reason I always give my metalic materials an IOR=10-15. The best thing to do is make a sphere with reflective environment and play with the Mix Curve and you'll see what I mean (make a sine curve to get some interestin effects)
3.Another trick ,I sometimes use, is to make a big sphere roughly the same size as the building. Make it to be chromic and than fine tune the position of your HDRI to match your light (sun) position.

Hope this might clarify things a little

Zoran

[flipside]

Hey zoranm!

But why do you use std material? Why not using a vraymat with fallof in the reflection slot (and fresnell unticked)? With the single planes, what is the advantage of std mat?