{"id":50182162,"url":"https://github.com/remvisual/td-brownianmotion","last_synced_at":"2026-05-25T07:05:26.043Z","repository":{"id":346718693,"uuid":"1191287134","full_name":"REMvisual/td-BrownianMotion","owner":"REMvisual","description":"Ornstein-Uhlenbeck brownian motion Script CHOP for TouchDesigner — smooth, mean-reverting procedural noise","archived":false,"fork":false,"pushed_at":"2026-03-29T21:12:21.000Z","size":782,"stargazers_count":2,"open_issues_count":0,"forks_count":0,"subscribers_count":0,"default_branch":"master","last_synced_at":"2026-03-29T22:22:41.935Z","etag":null,"topics":["creative-coding","generative-art","glsl","noise","ornstein-uhlenbeck","procedural","realtime","script-chop","td-olib-project","touchdesigner","touchdesigner-components","touchdesigner-tools","vj"],"latest_commit_sha":null,"homepage":null,"language":null,"has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":"mit","status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/REMvisual.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":"LICENSE","code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null,"zenodo":null,"notice":null,"maintainers":null,"copyright":null,"agents":null,"dco":null,"cla":null}},"created_at":"2026-03-25T05:04:58.000Z","updated_at":"2026-03-29T21:12:24.000Z","dependencies_parsed_at":null,"dependency_job_id":null,"html_url":"https://github.com/REMvisual/td-BrownianMotion","commit_stats":null,"previous_names":["remvisual/touchdesigner-brownian-motion","remvisual/td-brownianmotion"],"tags_count":1,"template":false,"template_full_name":null,"purl":"pkg:github/REMvisual/td-BrownianMotion","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/REMvisual%2Ftd-BrownianMotion","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/REMvisual%2Ftd-BrownianMotion/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/REMvisual%2Ftd-BrownianMotion/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/REMvisual%2Ftd-BrownianMotion/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/REMvisual","download_url":"https://codeload.github.com/REMvisual/td-BrownianMotion/tar.gz/refs/heads/master","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/REMvisual%2Ftd-BrownianMotion/sbom","scorecard":null,"host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":286080680,"owners_count":33464014,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2026-05-25T06:32:55.349Z","status":"ssl_error","status_checked_at":"2026-05-25T06:32:35.322Z","response_time":57,"last_error":"SSL_read: unexpected eof while reading","robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":false,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":["creative-coding","generative-art","glsl","noise","ornstein-uhlenbeck","procedural","realtime","script-chop","td-olib-project","touchdesigner","touchdesigner-components","touchdesigner-tools","vj"],"created_at":"2026-05-25T07:04:59.379Z","updated_at":"2026-05-25T07:05:26.016Z","avatar_url":"https://github.com/REMvisual.png","language":null,"funding_links":[],"categories":[],"sub_categories":[],"readme":"\u003cp align=\"center\"\u003e\n  \u003cimg src=\"https://github.com/REMvisual/td-BrownianMotion/releases/download/v2.0.0/banner-1280x640.png\" alt=\"Brownian Motion\" width=\"100%\"\u003e\n\u003c/p\u003e\n\n[![Download Latest](https://img.shields.io/github/v/release/REMvisual/td-BrownianMotion?style=for-the-badge\u0026label=Download\u0026color=blue)](https://github.com/REMvisual/td-BrownianMotion/releases/latest)\n[![Downloads](https://img.shields.io/github/downloads/REMvisual/td-BrownianMotion/total?style=for-the-badge)](https://github.com/REMvisual/td-BrownianMotion/releases)\n![Views](https://komarev.com/ghpvc/?username=REMvisual-td-BrownianMotion\u0026label=Views\u0026color=brightgreen\u0026style=for-the-badge)\n\nOrnstein-Uhlenbeck brownian motion for TouchDesigner. A Script CHOP that generates smooth, mean-reverting procedural noise with rotation support and fractal detail — perfect for organic camera drift, floating objects, generative motion, and anything that needs to feel alive.\n\n## What It Does\n\nUnlike random noise, Ornstein-Uhlenbeck motion always pulls back toward center — so you get natural, bounded wandering instead of unbounded drift.\n\n- **Exact OU math** — Gillespie 1996 analytical transition, zero discretization error\n- **Implicit spring** — Klak-style filter, unconditionally stable at any timestep\n- **Rotation noise** — independent OU process with its own speed and per-axis amplitude\n- **1/f pink noise detail** — Voss-McCartney algorithm adds organic micro-texture\n- **Per-axis range** — different min/max bounds per axis\n- **Speed-independent smoothing** — texture changes without affecting perceived speed\n- **Deterministic** — set a seed for repeatable motion\n- **26 automated tests** — validated at extreme parameters\n\n## Install\n\n**Requires TouchDesigner 2025+**\n\n1. **[Download the .tox](https://github.com/REMvisual/td-BrownianMotion/releases/latest)** from Releases\n2. Drag into your TouchDesigner project\n3. Wire the CHOP output to whatever needs motion\n\nOutputs six channels: `tx`, `ty`, `tz`, `rx`, `ry`, `rz`.\n\n## Parameters\n\n### Motion\n\n| Parameter | Default | Description |\n|-----------|---------|-------------|\n| **Speed** | `1.0` | Time-scale multiplier. 1 = real-time, 5 = 5x faster. 0 = frozen (instant stop). Transitions are smoothed. |\n| **Amplitude** | `1.0` | Output multiplier. 0 = silence, 1 = full range. |\n| **Center Pull** | `2.0` | How strongly motion pulls back toward anchor (theta). High = tight orbit. Low = lazy wander. 0 = pure Brownian, no pull. |\n| **Smoothing** | `0.5` | Spring filter. 1 = very smooth (~2s settling). 0 = minimal filtering. Controls texture, not speed. |\n| **Detail** | `0.0` | Voss-McCartney 1/f pink noise micro-texture. 0 = off. Respects Smoothing. |\n| **Detail Layers** | `3` | Fractal octaves for Detail (1-5). More = richer frequency content. |\n\n### Range\n\n| Parameter | Default | Description |\n|-----------|---------|-------------|\n| **Range Min / Max** | `[-1, 1]` | Output bounds. Normalized OU state maps to this range. Set to [0, 100] and channels wander between 0 and 100. |\n| **Per-Axis Range** | `Off` | Toggle per-axis min/max. On = each axis gets its own bounds. |\n| **Range Min/Max X, Y, Z** | `[-1, 1]` | Per-axis bounds (visible when Per-Axis Range on). |\n\n### Rotation\n\n| Parameter | Default | Description |\n|-----------|---------|-------------|\n| **Enable Rotation** | `Off` | Master toggle. When off, rx/ry/rz output zero. |\n| **Rotation Speed** | `1.0` | Independent speed for rotation. Separate from position Speed. |\n| **Pitch / Yaw / Roll** | `5 / 5 / 0` | Amplitude in degrees per axis. 0 disables that axis. Shares Center Pull and Smoothing with position. |\n\n### Axes\n\n| Parameter | Default | Description |\n|-----------|---------|-------------|\n| **Affect X / Y / Z** | `All on` | Per-axis enable toggles. Disabled axes output zero. |\n\n### Advanced\n\n| Parameter | Default | Description |\n|-----------|---------|-------------|\n| **Anchor X / Y / Z** | `0` | Drift target in normalized [-1, 1] space. 0 = center of range. 0.5 = hang out in upper half. |\n| **Seed** | `0` | 0 = unseeded (different every run). Any other value = deterministic, same motion after Reset. |\n| **Independent Axes** | `On` | ON = each axis gets its own noise (3D wandering). OFF = shared noise (lockstep diagonal). |\n| **Reset** | `Pulse` | Snap to anchor positions and re-seed. Fresh start. |\n\n## The Math\n\nThree-stage pipeline, all running without substep loops:\n\n**1. Exact OU Transition** (Gillespie 1996)\n\n```\ndecay = exp(-theta * dt)\nX = mu + (X - mu) * decay + sigma * sqrt((1 - exp(-2*theta*dt)) / (2*theta)) * Z\n```\n\nWhere `theta` is Center Pull, `mu` is Anchor, and `sigma = 0.55 * sqrt(2*theta)` is tuned so the stationary distribution fills ~80% of the [-1,1] range regardless of theta. Zero discretization error at any timestep.\n\n**2. Voss-McCartney 1/f Detail** (applied before spring)\n\nMultiple independent OU processes updating at halved rates (layer 0 every frame, layer 1 every 2 frames, layer 2 every 4, etc.), summed with halving amplitude. Produces true 1/f pink noise — the spectral profile humans perceive as \"natural.\" Added to the OU state before filtering so Smoothing controls detail too.\n\n**3. Implicit Spring Filter** (Klak-style)\n\n```\nvel = (vel - (pos - target) * omega^2 * dt) / (1 + omega * dt)^2\npos += vel * dt\n```\n\nUnconditionally stable at any timestep. Omega scales with `sqrt(speed)` so smoothing character is preserved at all speeds. Runs on real frame time (decoupled from simulation speed).\n\n## License\n\n[MIT](LICENSE) -- use it however you want.\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fremvisual%2Ftd-brownianmotion","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fremvisual%2Ftd-brownianmotion","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fremvisual%2Ftd-brownianmotion/lists"}