multimesh-highlight-rendering-pattern

name: multimesh-highlight-rendering-pattern description: Specialized Tier 3 contract for high-density board highlights using MultiMesh/MultiMeshInstance3D with deterministic instance data and performance-safe updates. tier: tertiary godot_version: 4.6+ doc_anchors: - godot-docs/classes/class_multimesh.rst - godot-docs/classes/class_multimeshinstance3d.rst - godot-docs/tutorials/performance/using_multimesh.rst - godot-docs/tutorials/3d/using_multi_mesh_instance.rst tags: - rendering - multimesh - performance depends_on: - godot-skills/godot-secondary/domain-rendering-visuals/SKILL.md

MultiMesh Highlight Rendering Pattern

Use When

• Rendering large highlight overlays or marker sets on tactical boards.
• Replacing large numbers of individual marker nodes with batched rendering.

Outcomes

• Highlight rendering scales via batched instance updates.
• Instance index/data mapping is deterministic.
• Visual feedback stays within profiling budgets.

Required Rules

• Use MultiMeshInstance3D as render node and MultiMesh as instance data container.
• Treat instance index assignment as deterministic data contract.
• Separate highlight data generation from rendering update application.
• Batch updates predictably; avoid per-instance scene-node churn.
• Keep material/custom-data channels explicit for state encoding.

Workflow

1. Define highlight state schema and stable instance indexing policy.
2. Populate MultiMesh transforms/custom-data from precomputed state.
3. Apply batched updates at controlled cadence.
4. Profile update cost and visible-instance behavior.
5. Add fallback behavior for extreme cardinality spikes.

Validation

• Repeated identical highlight inputs produce identical instance buffers.
• Profiler confirms update cadence stays within budget.
• Spike scenarios trigger fallback without frame collapse.

Failure Modes

• Instance ordering changes nondeterministically between frames.
• Per-instance node churn replaces batching and degrades performance.
• Custom-data channels are overloaded without explicit schema.

Local Doc Anchors

• godot-docs/classes/class_multimesh.rst
• godot-docs/classes/class_multimeshinstance3d.rst
• godot-docs/tutorials/performance/using_multimesh.rst
• godot-docs/tutorials/3d/using_multi_mesh_instance.rst