How to create a glass shader into which light can pass?

[CarlG]

I just posted this:

See-through glass material

For what renderer? I only do Cycles. Where glass is supposed to be a fresnel mix between refraction and glossy - in that order in the mix shader. Your mix with transparency is in reverse. I normally don’t bother with the diffuse and glossy shading replacement, only the shadow one because I can’t rely on caustics to do the job. So when the light is calculating shadow and hits the transparent shader, I also usually base its color on fresnel. But since it’s the reverse, I do a 1-fresnel to drive i…

Light will pass if you enable caustics and render for long enough. That transparency trick is for when you don’t have caustics enabled (or helping it out). There is no way to render glass accurately using transparency shadow trick, and there may be cases where what I did will fail miserably. But that is the technique I rely on. Full transparency for all shadow looks just broken imo.