“First steps, you will need at least two objects in your scene: the camera and any geometry mesh. Then you will need at least one Collection for obvious reason, note that you will need to place EVERY object you want to have an outline/line art into the collection.
“Go into camera view, make sure the camera is facing the object you want to have lineart, press Shift+A in your viewport, go to Grease Pencil > Collection Line Art. Then you will see that you have a new object called Line Art. Go to Modifiers Properties and set the line radius to something like 0.05. Keep in mind that the relative radius of the strokes varies with their absolute radius, which is the line radius value in the modifiers tab. This means: the closer the camera is to the object, the bigger its outline, because Blender handles the line art as a separate object, of course. With the help of a not-too-complex but maybe complicated driver setup, you can make the line radii static to every distance from the camera.”
