Baking a normal map

The file size of a 3D scan can be large. It can be reduced by removing surface details and faking them instead. A normal map is similar to a texture map, but instead of being rendered in color, it is interpreted by the render engine as surface details that catch the light or cast shadows.

  • Import the 3D file, scale, orient and set origin as needed. After scaling, apply scale (shortcut: ctrl + a > Scale).
  • Perform a general 3D scan cleanup if necessary.
  • Save the blender project as the high-resolution version. For example: scallop_hires.blend.
  • Save the same file, but name it as the lowres version. For example: scallop_lowres.blend.
  • Add the remesh modifier
    • Set the mode to smooth.
    • Set the Octree Depth to 8 and lower the Scale until you find a good spot between preserving the general shape and vertex count. Depending on the complexity of the object you might need to experiment with a different Octree depth.
    • Apply the modifier.

Reducing the file size of the mesh by remeshing the object.

  • In edit mode, recalculate normals. Mesh > Normals > Recalculate Outside (shortcut: shift + n).

A normal map is essentially an image texture wrapped around a 3D model. Images are flat, so we need to define how we will flatten the 3D object in order to create a reference where the texture will go. Look at the model and find lines where we can cut the model in order to flatten it without too much distortion.

  • Since the shell is a simple shape, I can make a single cut that separates both halves of the shell. If you have a more complex shape, more cuts can be made.\\Hint: select the shortest path between vertices with ctrl + left mouse button.
  • Mark the current selection as a seam. Edge > Mark Seam (shortcut: ctrl + e)

Marking the current selection as a seam.

  • Select all vertices
  • Unwrap. UV > Unwrap (shortcut: u)
  • Go to the UV Editing workspace to see how the unwrap turned out.

Unwrapping the object in the UV editing workspace.

  • 3d_modeling/blender/baking_a_normal_map.txt
  • Last modified: 2020/04/15 08:35
  • by formlab