I have a moderately complex scene that I wish to render in a "line only" style like blueprints. I've enabled freestyle rendering and stuck with the Workbench render engine given that I don't actually need anything other than the freestyle lines. There are no lights or textures in my scene and I only have a single line set. I'm rendering the lines as a seperate render pass and compositing them with a flat color background using an Alpha Over node in the compositor. The result is what I want, but it is very slow. Nothing in my scene moves other than the camera, so I've enabled View Map Cache as per the docs. But still, each frame is taking several minutes to render.

My PC is reasonably high spec (rtx 4090 and AMD 7700) and I've enabled GPU rendering, yet I'm only seeing a couple of cores being utilised during rendering and the GPU is barely used at all. I have plenty of free memory so I don't think paging is happening. I read in an older question that freestyle line rendering is a single core CPU only activity, but that was pre Blender 3 and I have read information elsewhere which seems to contradicted this so I'm not sure if that is still the case or not.

Is there anything I can do to speed up these renders/better utilise my hardware? Are there optimizations to speed up rendering if you only need the freestyle lines, or is this still a single core process that is inherantly slow?



You must log in to answer this question.

Browse other questions tagged .