a Grease Pencil object with a Geometry Nodes setup which
- generates geometry lines from the Grease Pencil lines
and
- assigns a refraction shader that smudges the objects behind the lines according to the Grease Pencil lines' size, strength, and direction.
👉彡 Smudge Pencil 彡 Create Smear Frames 彡 Geometry Nodes Setup for Blender 4.3+