Twilight Render User Forum

Two sheets of glass, each one with thickness, sun in same position, physical sky in both renderings, same scene, same position.
Maxwell Render vb Twilight Render(Easy 09.Interior Progressive).
In TW render, the shadows from blinds don't appear on wall. If I render wiht Easy Low-High, I see the shadows, but not on Progessive. I reduced the softness of Sun shadows to 10 (sharp), to be sure, but still nothing on wall.

Don't pay too much attention to scene elements, what is important is the shadow ! (more exactly the missing of shadow)

Which glass template have you used? Use common (thin) glass, not the flint one. No problems at all here: two sheets of glass (1mm of thickness) 1 cm distant each other. Rendered with easy 09.
If possible use always a single face with no thickness and thin glass applied on it for windows glasses.

massimo wrote:...
If possible use always a single face with no thickness and thin glass applied on it for windows glasses.

RECOMMENDED

The preferred "Thin Glass" material template for architecture is found here:
Template>Architectural Glass>No Shadow

To increase the reflectivity of the glass - increase the IOR from 1.52 (default) to 1.8 or 2.2

I hoped to achieve that double reflection (caused by refraction in glass thickness), this is why I used glass sheets with thickness. Normally, that should give me four reflections in glass (pairs of two, slightly offset from one another). Just a fad...
I'll try with your suggestions. thank you.

If you use Thin Glass, it's not a problem to have 2, or 4 faces in your glass. It may cause some consternation to the engine depending on the render settings, and it may increase render times while it calculates the inter-reflectivity, but it CAN handle it!

Try it!

You can achieve double refraction with Easy09 setting - just light scene with HDR, or use Light Emitter Surfaces to light the scene - then caustics are rendered with Easy 09.
Easy 10 you can use any lighting.

Best is, of course, to use thin glass as mentioned by Massimo and Alvydas.
Here I used 3dwarehouse component "Andersen Window" and copied the glass layer 3 times - 1 inside and 2 outside. Each are 1/16" apart (.1 or .2 cm)
All are Template Architectural Glass - No Shadow
Rendered on Easy 05 Medium+ and Easy 09.

Fletch wrote:just light scene with HDR, or use Light Emitter Surfaces to light the scene - then caustics are rendered with Easy 09.
Easy 10 you can use any lighting.

my scene was with Sun, does it make any difference? Is important to use HDR for lighting my scene?

In order to render light passing through a dielectric material (glass or water with refraction) you must render CAUSTICS.
Caustics are enabled in Easy 09 ONLY when you use certain types of lighting, this is because they are "physical" lighting. (just like Maxwell AFAIK... until fairly recently Maxwell did not have point lights either) So you have spots and point lights in Easy 09 - but Caustics are not rendered with them. So glass and water cast a shadow. (the sun is a point light) For caustics in Easy 09 light the scene with HDR or with light emitting surface, then the glass will not cast a shadow.