That’s interesting Emir, because I see the same behavior in both R19 and R20 that Hilary is seeing. Which version of C4D are you using? While I don’t have an answer for Hilary as to why this is happening, in watching a 2013 tutorial from 3DFluff (Physical Render Engine Speed and Quality in CINEMA 4D) on the standard versus physical renderers, he shows the same behavior, and he’s probably using R14 in that tutorial. I have been unable to find any related info in C4D’s help section concerning antialiasing and the Physical renderer, but I did notice that “Force Antialiasing” is also greyed-out in a Compositing Tag when the Physical renderer is selected.