evo-threejs-to-obj

evo-threejs-to-obj is a skill for Claude Code, Codex from OpenLAIR/OpenSkill. It costs 47 tokens per session (836 once invoked), scanned A, original, Apache-2.0.

A Node.js tool that converts Three.js scene graphs into Wavefront OBJ files for Blender. It handles nested objects, repeated mesh instances, transforms, and the different coordinate directions used by the two programs.

In plain words
What is it for?
It is for exporting complete Three.js models, including nested hierarchies and InstancedMesh objects, to OBJ for 3D editing.
Why use it?
It removes the need to export complex scenes manually or write special handling for repeated objects. It applies object transforms before converting the model to Blender’s coordinate system.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit It is for exporting complete Three.js models, including nested hierarchies and InstancedMesh objects, to OBJ for 3D editing.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/openlair/openskill/evo-threejs-to-obj
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add OpenLAIR/OpenSkill --skill evo-threejs-to-obj
Clone the repo
git clone --depth 1 https://github.com/OpenLAIR/OpenSkill

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for evo-threejs-to-obj

README.md
[![agentmods](https://agentmods.dev/badge/skills/openlair/openskill/evo-threejs-to-obj/github.svg)](https://agentmods.dev/skills/openlair/openskill/evo-threejs-to-obj)
Your own site
<a href="https://agentmods.dev/skills/openlair/openskill/evo-threejs-to-obj"><img src="https://agentmods.dev/badge/skills/openlair/openskill/evo-threejs-to-obj/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for evo-threejs-to-obj

Your own site · 80×15
<a href="https://agentmods.dev/skills/openlair/openskill/evo-threejs-to-obj"><img src="https://agentmods.dev/badge/skills/openlair/openskill/evo-threejs-to-obj.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 47 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 836 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00047 $0.00836
Opus 5 $0.00023 $0.00418
Sonnet 5 $0.00009 $0.00167
Haiku 4.5 $0.00005 $0.00084

Measured yesterday against content hash d4493abdcf65, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

evo-threejs-to-obj scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/convert.mjs), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

tasks-evolved/threejs-to-obj/environment/skills/evo-threejs-to-obj/SKILL.md · 86 lines

How it starts

The opening of the file, as written. The whole thing — 86 lines — stays where its author put it; the contents beside it link to each section on GitHub.

evo-threejs-to-obj

Purpose

Convert Three.js scene graphs to Wavefront OBJ format suitable for Blender (Z-up coordinate system).

Key Domain Knowledge

Coordinate System Conversion

  • Three.js: Y-up, -Z forward, right-handed
  • Blender: Z-up, -Y forward, right-handed
  • Apply -90° X rotation: X→X, Y→Z, Z→-Y
  • Rotation matrix Rx(-90°): [[1,0,0],[0,0,1],[0,-1,0]]
  • Applied AFTER world transform baking, BEFORE writing OBJ

Pipeline (per geometry)

  1. Clone source BufferGeometry
  2. Apply node's world matrix (or composed world*instance matrix for InstancedMesh)
  3. Apply -90° X rotation for Y-up to Z-up conversion
  4. Collect transformed geometry

InstancedMesh Handling

  • Each instance has a per-instance 4x4 matrix
  • Final transform: mesh.matrixWorld * instanceMatrix[i]
  • Must export each instance as separate geometry
  • Standard OBJExporter does NOT handle InstancedMesh - manual traversal required

Non-Uniform/Negative Scales

  • Apply full world matrix directly (don't decompose to pos/rot/scale)
  • Negative scale flips winding order
  • Decomposition loses shear from nested non-uniform scales

Geometry Preparation for Merging

  • Convert indexed geometries to non-indexed (toNonIndexed())
  • Compute vertex normals if missing (computeVertexNormals())
  • Remove extra attributes (UV, etc.) to ensure homogeneous attribute sets
  • Keep only 'position' and 'normal' attributes
  • Merge all into single BufferGeometry using mergeGeometries()

OBJ Export Strategy

  • Manual traversal with per-geometry transform baking (most reliable)
  • Merge all geometries into single Mesh
  • Pass single Mesh to OBJExporter (avoids exporter's limited traversal)

World Matrix Update

  • MUST call root.updateMatrixWorld(true) before reading any world matrices
  • Without this, child nodes carry identity/stale matrices (DR ref: cite 17, 18, 20, 21)

Scene Module Loading

  • The input object.js may export via different patterns:
    • export default function createScene() or similar named export
    • export function createScene()
    • May return a Mesh, Group, Scene, or Object3D
  • Must handle all common export patterns robustly

Read the full file on GitHub · 86 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 86 lines · 47 tokens per session scan A d4493abdcf65

Subscribe to this mod's changes

evo-threejs-to-obj is a skill published in the GitHub repository OpenLAIR/OpenSkill (90 stars, last pushed 2d ago), licensed Apache-2.0. It adds 47 tokens to every session and 836 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-11.

Related

Other skills, from other repositories

dialogue-graph

A library for building, validating, visualizing, and serializing dialogue graphs. Use this when parsing scripts or creating branching narrative structures.

Raidriar7170/hermes-skilleval · 32 tokens

audio-design

Implement game audio practice — bus/mixer architecture and gain in decibels, ducking (sidechain), adaptive/dynamic music via layering and re-sequencing, SFX variation, and beat synchronization. Engine-neutral. Use when the user mentions audio mixing, audio buses, adaptive/dynamic music, ducking, SFX variation, music…

gamedev-skills/awesome-gamedev-agent-skills · 81 tokens

threejs-world-generation

Build deterministic, editable, free-viewpoint Three.js worlds from text or structured briefs. Use for cinematic 3D terrain, semantic regions, procedural biomes, explicit landmarks, environmental scattering, camera fly-throughs, world diagnostics, or requests for a real 3D environment rather than generated 2D footage.…

calesthio/OpenMontage · 100 tokens

hatch-pet

Create, repair, validate, visually QA, and package Codex-compatible animated pets and pet spritesheets from character art, generated images, company or prospect brand cues, or visual references. Use when a user wants a lightweight-worker Codex pet workflow, a non-pixel custom pet style, a prospect or company mascot…

openai/skills · 118 tokens

animation-system

Use when implementing animations — AnimationPlayer, AnimationTree, blend trees, state machines, sprite animation, and code-driven animation.

jame581/GodotPrompter · 27 tokens

novel-to-game

Turn a novel into a fully playable game on the selected target platform. Orchestrates the whole adaptation pipeline — requirements intake, gameable deconstruction, concept selection, world and visual design, target-runtime build, and evidence-based QA — for a novel in any language. Use for novel to game, story to…

zenstory-ai/novel-to-game · 201 tokens