Lest it gets lost:
Compare the rendering with and without a dust layer stacked upon the glass base material tag.
Without: no distortion, as expected.
Without: distortion, where from?
Bug?
Win 10, R20, latest daily.
PS
Physical (render, the native one in C4D) does not "do" it.
PPS
Yeah, added dust makes the renderer think the glass object is massive, not hollow, and renders it this way. Detection problem where object ends or something like this.
