rendering fast multimatte without light ect. ends in bad edge

hello,
someone can explain me why this happens?
if i disable nearly everything only to render a fast multimatte of an object, the edge in the multimatte is really bad antialised.

thanks for help
thomes

this is due to vray basing its antialiasing on the contrast in the main render.. if you render all black, it assumes it doesnt need to do any AA if you are using bucket mode try increasing min AA setting

collegue had a vraymat with selfillumination on one object… so why doesnt this work?

was the selfilluminated object the same one with the multimatte ? this should give you nice edges on the object with the self illuminated material, but not the rest of the scene. did you try increasing the min AA?

i was wrong, worked with selfillu, sorry for that wrong feedback !