The glass BSDF has two main methods. Reflection and refraction.
The transparent BSDF has neither.
The question is, is it yet possible to make a gas-like material that has only refraction but no reflection?
It seems I can’t find out if it’s possible.
I’ve also no idea yet how to use Fresnel properly yet.
I´d be happy for every enlightment, else I got to ditch cycles for my current project and use Luxrender, which I don’t really want.