Reflection and Refraction characteristics of glass

[Nobody]

Hi,

I trying to render a interior scene using a HDRi map and a sun to get sharp shadows like Fernado Rentas did in his videotutorial.

http://software.asgvis.com/index.php...Video+Tutorial

in the first rendering:

http://dl.dropbox.com/u/14787541/110...%20Scheibe.png

i turned off the glass between the room and the court. As you can see, the reflections of the tree and the HDRI map are clearly sharp on the glass inside the court. (Even when the room got way to bright)

when i turn that glass on, like in this rendering:

http://dl.dropbox.com/u/14787541/110...20Scheiben.png

these reflections get a blurry gray. When i give that glass a very mean amount of reflection it still keeps the blurry result.

My question is: Why is the glass affecting the scene like that, and what can i do to keep the clear shadows and reflections?

Any help would be appreciated. A link to documentation likewise.



Cheers, Peter.

[Micha_cg]

Re: Reflection and Refraction characteristics of glass

There is a tutorial at the asgvis pages "making materials" with glass for architecture.

[Nobody]

Re: Reflection and Refraction characteristics of glass

Hi Micha,

thanks for your replay. I already studied these tutorials but it seams i dont really get whats wrong with my glass.
When i get the tutorial right a blurry result should only happen when i put the Glossiness in the refractionlayer below one.

And i still dont understand why its just affecting the reflactions of the tree and HDRI map while the rest of the geometry keeps clear.

maybe someone get a idea whats the issue,


thanks Peter

[Micha_cg]

Re: Reflection and Refraction characteristics of glass

Why not use the architecture glass without refraction layer:
http://software.asgvis.com/index.php...=30&Itemid=437

For your effects a simple explanation could be possible. What is your max depth of refr/refl? If this level is reached than ... I'm not sure, but maybe your tree reflections isn't blurry, it is invisible, because not calculated by the max depth limit. The grey is from the reflection of the wall/ceiling/floorground at the big window (you also see the reflection of the chairs).

An other problem is that you glass block the sun light. Did you enable "affect shadow" at the material?

[ValeroStudio]

Re: Reflection and Refraction characteristics of glass

I've tried all the tutorial methods and downloaded several material files but I have not figured out how to get a decent glass material. I dont know what Im doing wrong.

[arqestevez1]

Re: Reflection and Refraction characteristics of glass

haven't you tried with the software's presets?
i always use the "clear glass" that used to come with the 1.05.30 version...
that and the green glass too... and then you just have to play with the reflectivness

[ValeroStudio]

Re: Reflection and Refraction characteristics of glass

Ok, that glass material is actually pretty damn good. Man, there are some awful ones out there. I was using the 'architetural' glasses you get on the web. Whats the best way to reduce the reflection? Do you actually adjust the amount slider or the color from white to gray on the reflection setting? Or is it a setting within reflection parameters for the glass?

[arqestevez1]

Re: Reflection and Refraction characteristics of glass

I always leave the colors completely white, but in the reflection layer clic on the reflection m and change the IOR value... default setting is 1.55 i usually increase than value to 1.7 or 1.8, depending on how much reflection i want... i've increased it up to 4 in one scene, because i wanted more reflections...
sometimes it is worth to delete the refraction layer of the material, that when you make an exterior scene, for example, and you want to be able to watch what's inside the building... :P

[ValeroStudio]

Re: Reflection and Refraction characteristics of glass

I assume that IOR and Refract IOR need to be the same?

[arqestevez1]

Re: Reflection and Refraction characteristics of glass

no, just the one on the top... ;D

[Micha_cg]

Re: Reflection and Refraction characteristics of glass

Better don't touch the IOR and use the upper white color of the both fresnel colors to control the max reflection intensity. A higher IOR can be looking like a metal coating.