Better glass rendering

Glass is rendering quite poorly inside Enscape currently.

Here's an example what I mean. The first image is rendered with Thea and shows proper refraction of light passing through glass.

Here's a render with Enscape. The rays refract as if the object was not solid but made out of thin glass instead. The problem is obviously rays refracting twice, once passing through front face material and than again when passing through back face. There are also no shadows nor reflections on the floor.

Here's the same render but with transparency turned off. You can clearly see reflections and shadows on the floor.

Here's the scene if you want to play with it: glass test 3.zip

Note: the scene crashes if you try to render it to 4k.

Quote from Demian Gutberlet

Hey jure , the caustics of the glass in Thea you'd like to see in Enscape are rather difficult to render, even for offline renderers. Since Enscape is a real-time renderer, achieving the glass output possible with an offline rendering application like Thea is very hard to achieve, especially at 30-60 frames per second.

I'm more concerned with proper refraction and shadows than caustics. Caustics are really the last thing on my mind when doing arch viz.

Caustics and shadows are a different thing though. Caustics appear when light gets refracted or reflected and focused into a small area, and that area therefore appears brighter.

Glass (or transparent material for that matter) should still cast shadows since opacity (or transparency) of transparent material can be anywhere from 1-99%. Hence the shadow can be stronger or weaker. This has nothing to do with caustics though.