Blender: Convert 3D Mesh to Grease Pencil Line Art

Converting a 3D mesh outline into Grease Pencil art in Blender allows you to create stylized, 2D, or non-photorealistic rendering (NPR) effects directly from 3D models. By utilizing the Line Art modifier on a Grease Pencil object, Blender automatically calculates and generates vector stroke outlines based on your 3D geometry and camera perspective. This tutorial walks you through setting up your scene, applying the Line Art modifier, tweaking edge detection settings, and baking the strokes for further editing.

1. Set Up the Scene and Camera

The Line Art modifier relies on a camera view to calculate edge positions.

  1. Ensure your 3D mesh is placed in your scene.
  2. Add a camera if one does not exist (Shift + A > Camera).
  3. Align the camera to your desired view by pressing Ctrl + Alt + Numpad 0.

2. Add a Grease Pencil Object

You can add a pre-configured Line Art object or start with a blank Grease Pencil object:

  • Quick Method: Press Shift + A > Grease Pencil > Object Line Art (or Scene Line Art). Blender will automatically create a Grease Pencil object with the Line Art modifier already applied.
  • Manual Method: Press Shift + A > Grease Pencil > Blank. Then go to the Modifiers tab (wrench icon), click Add Modifier, and select Line Art.

3. Configure the Line Art Modifier

Select the Grease Pencil object and navigate to the Modifier Properties panel:

  1. Source Type: Choose how the modifier detects your 3D objects:
    • Object: Renders lines for a single specified mesh.
    • Collection: Renders lines for all meshes within a selected collection.
    • Scene: Renders lines for everything visible in the scene.
  2. Source: Select the target mesh or collection corresponding to your chosen Source Type.
  3. Layer: Choose or create the Grease Pencil layer where the generated strokes will reside.
  4. Material: Select a Grease Pencil material to define the color, thickness, and stroke style.

4. Fine-Tune Edge Detection Settings

Under the Edge Types section in the modifier panel, enable or disable specific line types to get the desired look:

  • Contour: Creates outlines around the silhouette of the mesh.
  • Crease: Generates lines along sharp angles. Adjust the Crease Threshold slider to control how sharp an edge must be to generate a line.
  • Intersection: Draws strokes where two different mesh surfaces intersect.
  • Material Borders: Draws lines where different materials meet on the same mesh.

Under the Style panel, you can adjust the Thickness and Opacity of the generated lines to match your art style.

5. Bake to Keyframes (Optional)

By default, the Line Art modifier is procedural and updates in real time. If you want to manually edit the strokes, sculpt them, or use them in frame-by-frame animation:

  1. Select your Grease Pencil object.
  2. In the Line Art modifier panel, click the dropdown arrow next to the modifier name and select Bake Line Art or go to the Bake section at the bottom of the modifier settings.
  3. Choose Bake to Keyframes for static frames or active animations.

Once baked, the strokes become standard Grease Pencil data that you can edit using Draw, Edit, or Sculpt modes.