Create Landscape Displacement Maps with GIMP Simplex Noise

This guide provides a direct, step-by-step workflow for generating smooth, organic landscape displacement maps (heightmaps) in GIMP using the GEGL Simplex Noise engine. You will learn how to configure your canvas with the correct bit depth to eliminate banding, dial in optimal noise parameters for natural topography, shape elevations using curves, and export high-precision maps ready for 3D applications or rendering engines.

1. Configure a High-Precision Canvas

Displacement maps require high precision to prevent stair-stepping artifacts during 3D displacement. Standard 8-bit images only provide 256 elevation levels, which causes visible terraces in terrain geometry.

  1. Open GIMP and navigate to File > New.
  2. Set your canvas dimensions to a square power-of-two resolution, such as 2048 × 2048 or 4096 × 4096 pixels.
  3. Go to Image > Precision.
  4. Select 16-bit floating point or 32-bit floating point, and set the channel encoding to Linear light for mathematically accurate elevation calculation.

2. Apply the GEGL Simplex Noise Operation

Simplex noise generates continuous, smooth gradients that mimic natural continental shelves, rolling hills, and mountain bases better than classic Perlin noise.

  1. Create a new transparent layer named Terrain Base.
  2. Navigate to Tools > GEGL Operation...
  3. In the Operation drop-down menu, choose gegl:simplex-noise.
  4. Adjust the operational parameters:
    • Scale: Controls the frequency of the landmasses. Set this to a lower value (around 0.001 to 0.005) to generate broad, rolling continental masses rather than high-frequency static.
    • Iterations (Octaves): Controls surface complexity. A value of 4 to 6 introduces secondary ridges and foothills without adding excessive roughness.
    • Seed: Change this value randomly to generate a new landscape variation until you achieve a preferred natural distribution of masses.
  5. Click OK to commit the operation.

3. Shape Elevations with Color Curves

Raw simplex noise yields a uniform bell-curve distribution of values, whereas real landscapes contain distinct geological features such as flat valleys, gentle plains, and sharp peaks.

  1. Go to Colors > Curves...
  2. Ensure the Value channel is selected.
  3. Shape the curve:
    • Flatten the bottom left: Pull the lower end of the curve down and keep it flat along the bottom to create flat plains, ocean floors, or river basins.
    • S-Curve the middle: Create a gentle upward slope through the midtones to represent gradual hill slopes.
    • Steepen the top right: Create an aggressive upward curve near the highlight area to force high-altitude areas into sharp peaks and ridgelines.
  4. Click OK.

4. Layer Secondary Details (Optional)

To add realistic variation such as sediment drift or fine surface erosion:

  1. Create another layer above Terrain Base named Terrain Detail.
  2. Run Tools > GEGL Operation... > gegl:simplex-noise again.
  3. Double or triple the Scale relative to the base layer to create tighter, smaller noise pockets.
  4. Set the Terrain Detail layer blend mode to Overlay or Soft Light.
  5. Lower the layer opacity to between 10% and 25% so it accents the primary landforms without dominating them.
  6. Right-click the top layer and select Merge Down into a single grayscale heightmap.

5. Export the Displacement Map

Retaining the high dynamic range during export is crucial for 3D displacement.

  1. Go to File > Export As...
  2. Name your file with a .png, .tif, or .exr extension.
  3. In the format export dialog:
    • For PNG: Choose 16bpc RGB or 16bpc Gray.
    • For TIFF: Ensure compression is set to None or LZW, with the data type retained as 16-bit or 32-bit float.
  4. Click Export to generate the final displacement map.