problems with glass

[mascab]

Hi,
the first image is rendered without glass, the second with it.
The glass material is visualized in the third image.
In my opinion it's too reflective, and the situation does not change even if i turn the black, in fresnel chanel inside specular, towards gray.
With that windows, i should have enough light inside the house to let me see interiors.
What do you think? Where is my mistake?

[big K]

hi mascab,

- lower your IOR to 1.5 i think this is more like glass. this won´t bring much , but a bit less reflection.
- most important turn off back side. this gives the backsides of surfaces also reflections. (you almost double your reflections)
- the last point does not do anything to the reflections, but if you use volume in the refraction layer you should raise the value of the distance bias a bit, or it won´t do anything.

hope this helps
michael

[GIOLETS]

My opinion is:
- use the reflection layer for reflections, IOR around 2,
- check your normal direction(aim them towards your Camera),
- extrude your glass object (0,5-1 cm) if is a single plane,
- uncheck the "enable volume" feature.

Bye.

Luca

[stefan]

your glass material looks ok to me, not the rendering though, so some is wrong in your setup.

in addition to the above opinions i also think there is more a problem with the glas geometry,
is it single plain--then you shoudl not sue a volume glass.

the refelction you indeed lower as you say if you set the fresnel to light grey. if that doesnt work youir problem is more in the geometry or inversed faces.
i guess the glass geometry is no proper volume ...with this glas setting you normally dont get such strange glass.

without seeing the actual file ist very hard to tell where your error is
maybe post it:-)

cheers
stefan

[mascab]

ok. i've done some experiments...
the glass has already a thickness of 1 cm, and the normals are ok.
Without volume and back face the situation is a little better but i don't understand why i have a variation of color inside.
It seems that the wood floor generates gi only if glass is present.
The cutoff parameter allows me to have a little more control on intensity of reflection, but honestly, i don't know why and what it is!

the model comes directly form allplan.
i've connected all the objects by material, with the aim of reduce the time of exporting objects.
i can't upload the file because it's a project and i don't have the permission.

i must admit that i think there's a geometry problem too, because render takes too much time!

[stefan]

maybe the volume parts are not connected, try an optimze of all glas objects:-)

it is definitly some wrong in your modell from the things you say.
you can also send me the file to the info adress if you want direct help.(see me under nda)

cheers
stefan

[GIOLETS]

You can also do a very simple and fast test: just make a vertical plane in C4D and position it at the same point of your glasses. Turn off the original glasses.
Extrude the plane (0,5-1cm) and apply on it your glass material.
Make a fast render and see the results: if it is the same or different respect your original windows...

[mascab]

already done...
the result is the same.
so it's not a problem of geometry of glass object (even if the ehole model is not optimized), but it's a problem of light...
I have also moved the glass toward the camera, and when it is directly illuminated, it's ok.
My opinion is that without direct illumination on it (even if there enough light to see the interior), the glass solves the problem pumping the reflections.

[stefan]

well anything you setup unnatural then.
glas of course needs nice enviroment and good light.

as you say the glass doenst ract to your changes i still think some is wrong there in either your glass or your modell.

without seeing the file it is very hard to help you. ..
try to seup lights as most real as you can, with real intesities etc.
use colormapping. real world light intensity in watts etc...

cheers
stefan

[mascab]

phisical sun e and phisical camera.
no artificial lights.
it's a simulation to calculate shadows inside...