# Procedural Geometry > Use when generating or reviewing the GEOMETRY of a game — procedural terrain, meshes, structures, and scatter. Covers noise as the substrate (Perlin/Simplex/value noise, fractal Brownian motion, domain warping), terrain generation (heightfield vs voxel/SDF, marching cubes, dual contouring, hydraulic/thermal erosion, LOD/chunking), structural generation (L-systems, shape grammars, wave function co… - **Type:** Skill - **Install:** `agentstack add skill-rondorkerin-gamestack-procedural-geometry` - **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior - **Seller:** [rondorkerin](https://agentstack.voostack.com/s/rondorkerin) - **Installs:** 0 - **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills) - **Latest version:** 0.1.0 - **License:** MIT - **Upstream author:** [rondorkerin](https://github.com/rondorkerin) - **Source:** https://github.com/rondorkerin/gamestack/tree/main/plugins/gamestack/skills/procedural-geometry ## Install ```sh agentstack add skill-rondorkerin-gamestack-procedural-geometry ``` Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent. ## About # Procedural Geometry How to generate the *geometry* of a game — terrain, meshes, structures, and scatter — so it is **correct** (watertight, manifold, properly wound, performant) and **varied** (perceptually distinct, not parametric oatmeal). Geometry generation is engineerable math: noise as a substrate, modulation and erosion for believability, constraints and hand-placed anchors for "designed-looking" structure, blue-noise for scatter, and topology validators as the non-negotiable correctness floor. > **Tier:** technical craft (→ `gamestack-core`). Engine-agnostic geometry-generation math underneath generated terrain, structures, and meshes. ## When to use this - Generating terrain (heightfield or voxel/SDF), and deciding which representation the design actually needs - Choosing and wiring a mesh-extraction (marching cubes vs dual contouring), erosion, and LOD/chunking pipeline - Generating structures with L-systems, shape grammars, or wave function collapse / model synthesis - Authoring the **mesh topology validator** (winding/normals, manifold, degenerates, watertight) - Scattering vegetation/props with blue-noise placement, environmental masking, and instancing - Diagnosing terrain that looks like "noise", structures that read as generated, or meshes with black faces / broken collision ## Scope This skill owns **the math and algorithms that produce geometry** — meshes, terrain, structures, scatter. It is deliberately narrow. Adjacent concerns live in sibling skills: - *What content means and whether it's perceptually varied at scale* (quests, lore, items, the oatmeal problem for **content**) → `procedural-generation`. This skill is the geometric statement of the same hybrid (hand-anchor + constrained fill); that skill is the narrative one. - *Making a generated level legible, navigable, gated, and paced* → `level-design`. This skill is the **geometry engine underneath** it — grammars/WFC produce the rooms; `level-design`'s principles make them readable. Geometry serves legibility; it does not replace it. - *Gating generated output for perceptual sameness and intentionality* → `procgen-review`. Its **oatmeal test** runs on the geometry this skill emits; the topology validator here is the *correctness* floor below that *quality* gate. - *Rendering, culling, and draw-call budgets for the meshes produced* → `3d-graphics-and-rendering`. *Texturing/shading them* → `shaders-and-vfx`. - *Macro/world spatial layout, biomes as places, exploration pull* → `open-world-design` (this skill is the terrain math underneath that layer). ## How the pieces fit - **`GUIDE.md`** — the cited *why*, in five sub-domains: noise as the substrate (Perlin/Simplex/value, fBm, multifractal/ridged, domain warping, Worley/3D-noise caves); terrain generation (heightfield vs voxel/SDF, marching cubes vs dual contouring, erosion, LOD/chunking); structural generation (L-systems, shape grammars, WFC/model synthesis, hybrid hand-anchor); mesh topology correctness (winding/normals, manifold/watertight, degenerates, runtime threading/caching); and vegetation/scatter (blue-noise, masking, instancing). Each rule carries an exemplar + source, a **test-for** criterion, the named failure mode, and the **procedural/headless implication**. - **`CHECKLIST.md`** — Do/Don't + machine-checkable **Test-for** criteria, grouped by sub-domain. Written to be enforced as validators in a generation loop. ## The two ideas to anchor on > **1. A single noise field is oatmeal; structure comes from modulation, not octaves.** Plain fractal Brownian motion is the canonical "fake terrain" look — equal roughness everywhere, no ridgelines, no drainage. Believability comes from *modulating* it (multifractal/ridged noise, domain warping) and from **erosion simulation** that carves the connected valleys and ridges a process would. More octaves add detail, not structure. > **2. "Looks designed, not random" is a constraint problem.** Grammar- and constraint-based methods (L-systems, shape grammars, wave function collapse / model synthesis) get their authored quality from **hand-authored rules and tilesets**, not from the algorithm. The designer's craft moves into the constraint set — and the most reliable path at scale is **hybrid**: hand-place the silhouette landmarks and set pieces, let the generator fill between them under constraints. > **Why this matters doubly for a generator:** a human sees a black inside-out face, a grid-aligned forest, or 10,000 identical buildings and feels "off." An autonomous generator has no eyes. Author the **mesh topology validator** (winding/manifold/degenerate/watertight) and the **representation, erosion, crack-free, and instancing contracts** as inviolable; let generation vary inputs *inside* them (frequency, octaves, density masks, seeds); and gate every batch through `procgen-review`'s oatmeal test for *geometric* sameness — because parametric variation of one formula produces perceptually identical results. Start with `GUIDE.md`, then apply `CHECKLIST.md`. ## Source & license This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code. - **Author:** [rondorkerin](https://github.com/rondorkerin) - **Source:** [rondorkerin/gamestack](https://github.com/rondorkerin/gamestack) - **License:** MIT Install and usage instructions live in the source repository linked above. ## Pricing - **Free** — Free ## Security capabilities Automated source analysis of v0.1.0 — what this tool can access: - **Network access:** no - **Filesystem access:** no - **Shell / process execution:** no - **Environment & secrets:** no - **Dynamic code execution:** no *"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.* ## Versions - **0.1.0** — security scan: passed — Imported from the upstream source. ## Links - Listing page: https://agentstack.voostack.com/l/skill-rondorkerin-gamestack-procedural-geometry - Seller: https://agentstack.voostack.com/s/rondorkerin - Browse the marketplace: https://agentstack.voostack.com/browse --- Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.