[fv]

I am in job trying to render glass with a transparent gradient image glued to backside of the glass. Its for a building.

I succeeded in doing the image with 2 projectors with different scales. The gradient is different from the image.

The glass has a thickness (20mm) and the image is at the back surface of the pane.
Now, when I render the glass its always too dark. It looks like smoked glass. I am now rendering up to SL40 hoping for better results. Up to 20 its still not good.

I am on a Macpro, here are the images
http://homepage.mac.com/fillieverhoeven ... index.html

Any help is appreciated. Maybe I should have a pane of 20mm glass and seperate geometry for the image like a very thin pane behind the glass.
The gradient is in the weight layer and the image is in the reflectivity layer of the material.

I have to take into account that when this pane of glass is ok I have render dozens fixed on the building so maybe using "real" glass is not an option. Maybe Maxwell just can't do glass properly as the rumor goes....


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[Bubbaloo]

Have you tried using AGS?

[pipcleo]

try hiding the glass from GI

[Mihai]

You probably need a separate plane behind the glass, and you could apply an AGS to the glass part if you don't need any refractions.

[fv]

Mihai, What do you mean by an AGS. The whole glass geometry as AGS or just some surfaces of the glass geometry. Will try though. Its getting better although the Ivy does not tile even when the mxm gallery had it offered as tiled. I suppose there aren't really tileable textures in the gallery. I haven't seen any yet truly tileable.

Thanks, indeed an extra plane was needed since the back surface of the glass had the normals facing the viewer. I added an extra plane 1mm behind the 20mm glass.

Here is the new image.
On the thirfd image you can clearly see what happens if the back surface of the glass has the normals in the wrong direction.


http://homepage.mac.com/fillieverhoeven ... index.html

[fv]

Am rendering now with AGS.
Will post the results later. AGlass looks bad but the horrible shades have gone.

Funny, now I am rendering with a lightsimulator and of all things it can't do glass....

[Mihai]

The problem with glass is when you want to see the caustics it generates through the glass. That's why the shadow from it looks too dark, it can start to clear but you need really really long render times for that. So AGS can have a very similar look if you don't need refraction effects. For thin glass panels it won't matter that much. You can tweak the reflective layer instead to get the surface of AGS more or less reflective.

[fv]

Thanks Mihai. I understand that wanting it all is just expensive, in term of rendertime. But AGS really looks very different in case you like to see the edges stand out as glass. In my case the glass facade is going to be just glass panes with open seams.
I tested again and the results are here.
http://homepage.mac.com/fillieverhoeven ... index.html

AGS is kind of dull. Glass has such weird shades that it does not work out at all. The really long rendertimes are not an option.

[Bubbaloo]

Try this:
Use AGS on the front and back planes of the glass while applying high grade glass material to the edges (and make them rounded, not flat). I have had good results using this technique.

[fv]

Thanks, will try that. But rounded, your joking right.... Tons of sheets of glass like this in this project...

(I switched the music off....you may need to switch it on again...lol.)

[fv]

you have an impressive gallery Bubbaloo

I think in general it is not understood how difficult or different it is to render a building as such that one percieves it as architecture. It requieres different skills and knowhow and a different userinterface of the application than you need for photorealistic rendering of smaller objects.

[Bubbaloo]

I think in general it is not understood how difficult or different it is to render a building as such that one percieves it as architecture. It requieres different skills and knowhow and a different userinterface of the application than you need for photorealistic rendering of smaller objects.

Definately! It's a whole different monster.

And thanks!

[numerobis]

i have got good results using real glass and a box hidden to gi.
behind this glass panel i've placed a plate with the printed colors clipped to dots - like in real life

[fv]

that trick with real glass edges worked out best sofar. I rounded the edges, or just bevelled them into 3. The big surfaces remained rendered in AGS.
http://homepage.mac.com/fillieverhoeven ... index.html

Hidden to GI also works at times but it can also make a render look dull. Its easy to change materials in Studio so usually I just try.

With a little more refinement this technique will workout with glass that can be seen at the edges. In windowframes I will from now on render in AGS only. "real" glass is simply worhtless in architectural renderings. So, unbiased rendering is not an option if you like to make it look real before and behind the glass. I think all agree.

[pipcleo]

This is all real glass , all hidden to GI , with the left balustrade glass slightly tinted.....but shadows DO work as expected
Should work as you want.... with the separate object behind as suggested