Legacy Normal Maps

Legacy Normal Map Packing

Older BeamNG content and third party assets may use different normal map channel layouts depending on the compression format and type. Modern workflows standardize this to BC5 (RG) normal maps, but legacy formats may require conversion to work correctly.

Channel packing formats

Different formats store the X and Y components of the normal in different channels:

Modern standard

The engine expects:

• BC5 compression
• X → Red channel
• Y → Green channel
• OpenGL tangent space (Y+)

Converting legacy normal maps

When working with older assets, you may need to repack channels:

• 3Dc (G,R)
  Swap channels → R = G, G = R

• DXT5nm (A,G)
  Move channels →
  R = Alpha,
  G = Green

• Incorrect Y direction
  If lighting appears inverted, flip the green channel (Y).

After conversion:

• Save as *.normal.png
• Let the Texture Cooker convert it to BC5

Recommended workflow

• Always use RGB 8-bit PNG as source
• Store normals in R (X) and G (Y)
• Keep textures in linear color space
• Avoid manually creating DDS unless necessary

Common issues

• Wrong lighting direction → Y channel inverted
• Flat or broken shading → incorrect channel packing
• Artifacts or compression issues → not using BC5

Notes