I have not yet found a to get the exhaust less regular. I don't want to use postwork untill I know fore sure that there is no more that can be done using the materials. In the Cruiser image the trail is volumetric lights and in the fighters it's the lightbeam material. I will have to experient some more ;) By the way. is there a way to tell witch parts in a scene that should be rendered and witch should not?