gn-instance-grid

GN Instance Grid

A runnable example that builds a generative Geometry Nodes tree — Mesh Grid → Instance on Points → Realize Instances → Transform → Set Shade Smooth — and attaches it as a NODES modifier, following the geometry-nodes-python skill. The tree has no Group Input: the grid and cube primitives live inside the node group.

What it witnesses: instancing is not free geometry until you realize it. The check asserts the closed-form evaluated topology — verts = grid points × cube verts (3 × 3 × 8 = 72), faces = 9 × 6 — that a Set Material node carries the lime accent, and that the corner instance center sits at its closed-form grid coordinate. If Realize Instances is omitted, the evaluated mesh is empty and the counts fail.

Run

# Cheap correctness check (no render) — the CI check:
blender --background --python gn_instance_grid.py --

# Also render a still (EEVEE on a GPU host; use --engine cycles on GPU-less hosts):
blender --background --python gn_instance_grid.py -- --output grid.png
blender --background --python gn_instance_grid.py -- --output grid.png --engine cycles

It exits non-zero on failure (wrong carrier, topology mismatch, missing material, or misplaced corner). The blender-smoke workflow runs the check on Blender 4.5 LTS and 5.1.