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name: terrain-mesh-and-analysis description: "Use BlenderGIS terrain meshing, object drop, globe/curvature, and terrain analysis material workflows." disable-model-invocation: true metadata: disco-role: operating license: GPL 3.0

Terrain Mesh and Analysis

Use this sub-skill when a BlenderGIS task needs terrain point-cloud meshing, Voronoi diagrams, dropping objects onto a terrain surface, transforming lon/lat meshes to a globe, applying earth-curvature correction, or building/reclassifying terrain analysis materials.

Route Here For

• bpy.ops.tesselation.delaunay() and bpy.ops.tesselation.voronoi(...) terrain point-cloud triangulation/diagram work.
• bpy.ops.object.drop(...) workflows where selected objects must be dropped onto the active ground object.
• bpy.ops.earth.sphere(radius=...) and bpy.ops.earth.curvature() mesh transforms.
• bpy.ops.analysis.nodes() and bpy.ops.reclass.* terrain height/slope/aspect material setup and color-ramp reclassification.
• Preflighting an XYZ point cloud with scripts/validate_point_cloud.py before running the Delaunay/Voronoi operators.

Route Elsewhere

• Importing shapefiles, OSM, contours, rasters, DEMs, or point source files belongs to the vector or raster/DEM sub-skills first.
• Creating or repairing scene CRS/georeferencing belongs to georeferencing-and-crs.
• Camera placement, EXIF geophotos, georeferenced rendering, and world-file output belong to geocameras-and-rendering.

Required Reading

1. references/workflows.md for complete step-by-step workflows and recovery paths.
2. references/operator-reference.md for operator IDs, options, selection/context requirements, inputs, and outputs.
3. references/troubleshooting.md when an operator cancels, logs warnings, silently skips objects, or produces a material/node result that does not look right.
4. scripts/validate_point_cloud.py for an offline point-cloud preflight helper that reads CSV or whitespace XYZ points and reports duplicates, same-XY different-Z points, too few unique points, and colinear XY geometry.

Operating Notes

• Delaunay and Voronoi use XY coordinates for topology. Z is retained for Delaunay terrain height but ignored by the 2D Voronoi diagram output.
• BlenderGIS mesh tools expect object-mode selections. Exact active-object and selection state matters; fix that before changing operator options.
• Terrain analysis node setup assumes a mesh-like active terrain object and forces the render engine to Cycles.
• Reclassification operators are Node Editor tools. They act on the active ShaderNodeValToRGB color ramp node, not merely on the selected mesh object.