Blender Grease Pencil Depth of Field & Motion Blur

Rendering Grease Pencil strokes with realistic camera effects like Depth of Field (DoF) and Motion Blur in Blender requires configuring your camera settings, render engine properties, and the 3D interaction settings of your Grease Pencil object. By properly setting up your scene in EEVEE or Cycles, you can seamlessly integrate 2D hand-drawn artwork with 3D depth and cinematic movement.

Setting Up Depth of Field for Grease Pencil

To apply Depth of Field to your Grease Pencil strokes:

  1. Select the Active Camera: Click on your camera in the 3D Viewport or the Outliner.
  2. Enable Depth of Field: Go to the Camera Properties tab (green camera icon) in the Properties panel and check the box next to Depth of Field.
  3. Set the Focus:
    • Choose a target object in the Focus on Object field, or manually adjust the Focus Distance slider to align with the depth of your Grease Pencil strokes.
  4. Adjust Aperture: Expand the Aperture section and lower the F-Stop value (e.g., 1.4 or 2.8) to create a stronger blur effect on strokes outside the focal plane.
  5. Adjust Stroke 3D Interaction: Select your Grease Pencil object, go to the Object Data Properties tab (green squiggle icon), and under Strokes, ensure that the Stroke Depth Order is set to 3D so strokes properly blend with scene depth rather than rendering as a flat 2D overlay.

Setting Up Motion Blur for Grease Pencil

Motion blur in Blender is calculated based on movement between frames. For Grease Pencil, motion blur works most reliably on object-level transforms (movement of the Grease Pencil object itself, camera movement, or armature deformations).

  1. Enable Motion Blur in Render Settings: Go to the Render Properties tab and check the Motion Blur option.
  2. Configure Shutter Settings:
    • Adjust the Shutter value (default is 0.5). Higher values increase the length of the blur trail, while lower values reduce it.
    • Set the Position to determine whether the blur occurs before, during, or after the current frame (default is Center on Frame).
  3. Animate the Object or Camera:
    • Ensure your Grease Pencil object is moving through 3D space via Keyframed Object Transforms (Location, Rotation, Scale) or bound to a rigged Armature.
    • Note: Hand-drawn, frame-by-frame stroke substitutions on individual frames do not generate native motion vectors. For frame-by-frame drawings, apply movement using an Armature, Lattice, or Object translation to produce the motion blur calculation.

Alternative Motion Blur via Compositor (Vector Blur)

If native motion blur is not producing the desired effect for deformed strokes:

  1. Go to the View Layer Properties tab and enable the Vector (or Speed) pass under the Passes section.
  2. Open the Compositing Workspace and check Use Nodes.
  3. Add a Vector Blur node (Shift + A > Filter > Vector Blur).
  4. Connect the Image, Z (Depth), and Speed outputs of the Render Layers node into the corresponding inputs of the Vector Blur node, then connect the output to the Composite node. Adjust the blur factor to achieve the final look.