SRTM Terrain Importer

This addon imports SRTM (Shuttle Radar Topography Mission) HGT files and creates accurate 3D terrain meshes with proper real-world scaling and elevation-based materials.

What are SRTM HGT Files?

SRTM HGT files contain digital elevation data collected by NASA's Shuttle Radar Topography Mission. This mission mapped nearly the entire Earth (between 60°N and 56°S) using radar interferometry. The data is available in two resolutions:

• SRTM1 (1 arc-second, approximately 30 meters resolution)
• SRTM3 (3 arc-seconds, approximately 90 meters resolution)

Each .hgt file covers a 1° × 1° tile of terrain and is named according to its coordinates (e.g., "N37W122.hgt" covers the area at 37°N, 122°W).

Features

• Accurate Scaling: Terrain dimensions are automatically calculated based on latitude
• Real Elevation Data: Heights are preserved in real-world meters
• Smart Materials: Automatic creation of elevation-based color gradient materials
• Customizable Settings:
  • Adjustable vertical scale for height exaggeration
  • Controllable mesh subdivision levels
  • Choice of color schemes (natural terrain or grayscale)
• Convenient Import: Supports both traditional file selection and drag-and-drop

How to Use

1. Importing Terrain:

   • Method 1: Go to File > Import > SRTM HGT (.hgt)
   • Method 2: Simply drag and drop .hgt files into Blender window

2. Import Options:

   • Subdivisions: Control mesh detail (10-200)
   • Vertical Scale: Adjust height exaggeration (0.1x - 5.0x)
   • Color Scheme: Choose between natural terrain colors or grayscale elevation map

Getting SRTM Data

Visit https://dwtkns.com/srtm30m/ to browse and select terrain tiles Create a free NASA Earthdata account at https://urs.earthdata.nasa.gov/ if you don't have one Download the desired .hgt files Files are named based on their coordinates (e.g., N37W123.hgt)

Use Cases

• Landscape Visualization: Create accurate representations of real-world terrains for visualization
• Scientific Terrain Analysis: Study geographical features and elevation patterns
• Game Level Design: Use real-world terrain data as a base for game environments
• Environmental Studies: Analyze topographical features and watersheds
• Architecture Site Planning: Understand site topography for construction projects
• VFX Background Creation: Generate realistic terrain backgrounds for visual effects

Technical Details

Mesh Creation

• Generated meshes are properly scaled based on latitude
• Each vertex position corresponds to real-world coordinates
• Automatic subdivision based on user settings
• Optimized for memory usage with large terrains

Material System

• Uses Blender's node system for elevation-based coloring
• Real-world height values drive the color gradient
• Displacement for accurate height representation
• Two color schemes available:
  • Natural terrain colors (default)
  • Grayscale elevation map

Metadata Storage

Each created terrain object stores:

• Latitude and longitude
• Minimum and maximum elevation
• Tile width and height in meters
• Original data resolution

Performance Considerations

• Mesh density affects viewport performance
• Start with lower subdivision values (around 50)
• Increase detail as needed
• Viewport clip range automatically adjusted for large terrains

Limitations

• Limited to areas covered by SRTM (60°N to 56°S)
• Some areas may have voids or artifacts in the source data
• Very large terrains may require significant memory
• Processing time increases with subdivision level

Version History

• 1.0.0 (2025)
  • Initial release
  • Basic terrain import functionality
  • Real-world scaling
  • Elevation-based materials
  • Drag and drop support