I am drawing a grease pencil layer over my subject based on a specific camera angle. The camera is locked, and the grease pencil strokes are being drawn while looking through it.
In order to draw the grease pencil layer properly, I need to be rendering the subject. However, if I viewport render, it impacts performance too much to comfortably draw. So I need some way to run a render and paint the grease pencil over it. I could render the subject and then paint over it with grease pencil in post, but I'm trying to keep the whole thing dynamic as there are other grease pencil elements that are not camera specific.
Is there a way to project a render back within the camera bounds so that it exactly lines up with the subject? Is there some other way to handle this issue?