The main render is done :) It took 9 hours in 1152x1536 ! Now i got to render the chains and their mask for compositing because of that transparency bug . Julian Boolean, my workaround might be good for my problem but not for yours . Did you try to render the background of your scene (with the fog) and then use the render as a backdrop for the foreground of your scene ? I hope it's clear ;) I'll post the image soon . litst