TouchDesigner Visuals
Node-based real-time synthesis — where signal, geometry, and code converge
TOP Pipeline
Texture OPerators are the visual backbone of TouchDesigner. Each TOP processes image data on the GPU, passing textures through a chain of compositing, filtering, warping, and feedback operations. The result feeds directly to output or into other operator families.
Feedback TOP
Routes the output texture back to an input, creating persistent visual memory. The gain parameter controls decay rate. Essential for trails, plasma, and recursive patterns.
Noise TOP
Generates procedural noise textures: Alligator, Sparse, Hermite, Random. Animated over time to produce organic movement without source material.
Composite TOP
Blends two textures using 20+ blend modes: Add, Multiply, Screen, Overlay, Difference. The building block of layered visual systems.
GLSL TOP
Runs custom fragment shaders directly on GPU. The most powerful operator for bespoke visual effects. Exposes full GLSL ES 3.0 capability.
GLSL Shaders in TouchDesigner
GLSL TOP and GLSL MAT operators give direct GPU access. TouchDesigner wraps standard GLSL with a set of uniforms (time, resolution, channel inputs) that make shader development fast. Live coding with immediate visual feedback is the standard workflow.
vec2 vUV (texture coordinate), float sampleRate, int sampleIndex. Channel textures accessed as uniform sampler2D sTD2DInputs[n]. Time available via uniform float uTime (set via Script CHOP or Info CHOP).
Fragment Shaders
GLSL TOP runs a fragment shader over every pixel. vUV gives normalized coordinates. Full floating-point precision for HDR effects.
Geometry Shaders
GLSL MAT supports vertex, geometry, and fragment stages. Animate geometry, generate particles, and apply per-vertex lighting in one operator chain.
Compute Shaders
TD 2022+ supports compute shaders via GLSL TOP in compute mode. Enables particle systems, fluid simulation, and mass geometry deformation on GPU.
Live Reloading
TouchDesigner hot-reloads GLSL files. External editors (VS Code + TD GLSL plugin) enable syntax highlighting and live preview with sub-second iteration.
CHOP Audio Reactivity
Channel OPerators process time-series data: audio, MIDI, OSC, sensor feeds. The audio analysis chain — AudioDevice In → AudioSpectrum → Analyze → Math → Export — turns live sound into control signals that drive any parameter in the network.
AudioSpectrum CHOP
FFT analysis producing frequency spectrum. Configurable bin count (64-4096), windowing function (Hann, Hamming, Blackman). Output: magnitude per frequency bin.
Analyze CHOP
Extracts scalar values from multi-channel signals: RMS, peak, average, or frequency-band energy. Converts waveform to control signal.
MIDI In CHOP
Receives MIDI CC, note, and clock data. Map note velocity to any parameter. Clock sync enables beat-accurate visual events.
OSC In DAT/CHOP
Receives Open Sound Control messages over UDP/TCP. Enables control from phones (TouchOSC), other computers, and modular synths.
SOP Geometry
Surface OPerators handle 3D geometry: mesh generation, deformation, particle systems, and import/export. SOPs connect to render pipelines via MAT operators and Render TOPs. TD's Python-scriptable SOP pipeline enables generative and data-driven geometry.
Particle SOP
GPU-accelerated particle system. Forces, constraints, and per-particle attributes. Connect to Point Instancer for mass geometry instancing.
Noise SOP
Displaces geometry vertices along noise field. Animating offset produces organic deformation. Frequency and amplitude control sculpt the effect.
Line MAT
Wire-frame rendering of SOP geometry. Essential for skeletal data visualization, particle trails, and minimalist aesthetic performances.
Point Instancer SOP
Places geometry instances at each point. Combine with Noise SOP to create organic particle fields. Render millions of instances in real time.
DAT Scripting & Data
Data OPerators handle text, tables, and Python scripts. Script DATs run arbitrary Python code with access to the full TD operator tree. Execute callbacks on frame cook, parameter change, MIDI event, or OSC message. The entire TD network is a live Python object graph.
op('noise1').par.transform.val = 1.5. Access any parameter on any operator by name. me.cook() forces recompute. parent().op('out1') traverses the network hierarchy. Python 3.x full standard library available.
Script DAT
Python code executed on each frame cook or triggered by events. Can read/write parameters, instantiate operators, query CHOP data, and interface with external APIs.
Table DAT
Spreadsheet-like data table. Drive operator parameters from CSV, configure routing, store state. Fundamental for data-driven and generative systems.
Web Client DAT
HTTP requests from within TD. Pull data from APIs (weather, stock prices, social feeds) and map it directly to visual parameters in real time.
Execute DAT
Callbacks for frame start, frame end, parameter change, keyboard, MIDI. The event system for reactive Python scripting throughout the network.
Network Architecture
Large TD projects decompose into modular Components (COMPs). Base COMPs encapsulate reusable systems; Container COMPs manage complex UI. Replicator COMPs instantiate operator sets dynamically. The network is a live scene graph that can be edited and extended during performance.
Component (COMP)
Container for sub-networks. Base COMP is a blank container; Geometry COMP is a 3D scene node; Camera, Light, and Render COMPs define the rendering pipeline.
Replicator COMP
Instantiates copies of a master COMP based on a Table DAT. Each row → one instance with unique parameters. Drives generative systems at scale.
Perform Mode
Hides the editor and runs TD in full-screen output mode. Custom UI panels built inside TD control the performance. Parameter panels stay accessible via keyboard shortcuts.
Multi-Output
TD supports multi-window, multi-monitor, and Spout/Syphon output simultaneously. A single network can drive multiple projectors via separate Out TOPs.
Artists & Practitioners
These creators have defined what TouchDesigner looks, sounds, and feels like — building public resources, tutorial libraries, and live performance aesthetics that the community continues to evolve.
Derivative Inc.
Creators of TouchDesigner since 1999 (as Houdini's interactive sibling). Maintain the platform, education resources, and the global TD community.
Matthew Ragan
Prolific tutorial library covering advanced TD techniques. Works in large-scale installation and teaches at ASU. Wrote the unofficial TD textbook.
Bileam Tschepe
YouTube channel with 300+ TD tutorials. Focus on generative systems, audio reactivity, and approachable explanations of complex TD workflows.
paketa12
Instagram and YouTube presence demonstrating high-performance real-time visuals. Aesthetic focus on organic geometry and audio-reactive systems.
Acrylicode
Noise-based generative systems, GLSL shader aesthetics. Known for tutorials combining mathematical concepts with immediately usable TD patterns.
Noto the Talking Ball
Combines TD with live coding environments. Develops systems at the intersection of algorithmic music and real-time generative imagery.
Interactive Immersive
Large-scale TD installations for events, museums, and permanent installations. Tutorial content focuses on projection mapping and sensor integration.
Amaan Akram
Performative live coding and TD composition. Explores the overlap between computational process and musical improvisation in real-time AV performance.
Glossary
Core vocabulary of TouchDesigner and node-based real-time visual synthesis.
- TOP
- Texture OPerator. Processes 2D image data on the GPU. All TOP outputs are textures. Named for their blue color in the TD network editor.
- CHOP
- Channel OPerator. Processes time-series data (audio, MIDI, sensor, animation curves). Output: channels of floating-point samples.
- SOP
- Surface OPerator. Handles 3D geometry: polygons, NURBS, particles, and point clouds. Green in the network editor.
- MAT
- Material OPerator. Defines surface shading: PBR, phong, wireframe, GLSL custom. Applied to geometry in Geometry COMPs.
- DAT
- Data OPerator. Handles text, tables, and Python scripts. The scripting backbone and data management layer of TD. Purple in the editor.
- COMP
- Component OPerator. Container for sub-networks (Base COMP), 3D scenes (Geometry COMP), and UI elements (Container COMP).
- Feedback TOP
- Routes its own output back as input with a one-frame delay. Enables persistent visual memory, decay trails, and recursive pattern generation.
- GLSL TOP
- Runs a custom fragment shader over a texture. The most flexible visual operator in TD. Access to all inputs as sampler2D uniforms.
- Replicator COMP
- Instantiates a master component N times, where N is driven by a Table DAT. Each instance gets unique parameters from table rows.
- Cook
- TD term for "compute." An operator cooks when its inputs change or it is forced to recalculate. Cook time visible in performance metrics panel.
- Export
- Binding a CHOP channel to an operator parameter. Right-click any parameter → Export → select CHOP channel. Updates on every cook.
- Expression
- Python expression evaluated live as a parameter value. E.g.,
op('noise1').par.txin a parameter field. Updates every frame. - Spout / Syphon
- Cross-application GPU texture sharing. Spout (Windows), Syphon (macOS). Share textures between TD and Resolume, MadMapper, VDMX, OBS.
- NDI
- Network Device Interface. Low-latency video streaming over LAN. TD supports NDI In/Out for sending video between machines on the same network.
- Perform Mode
- Full-screen output mode hiding the TD editor. Custom UI panels (Container COMPs) provide performance control without editor overhead.
- KinectAzure CHOP
- Driver for the Azure Kinect depth/skeleton sensor. Provides 3D skeleton joint positions as CHOP channels for body-tracking reactive visuals.
- TD Commercial License
- Commercial license required for for-profit use: $300/year (indie) or $600/year (pro). Educational/non-commercial use is free.
- Instancing
- Rendering millions of geometry copies with per-instance attributes (position, color, scale). Driven by CHOP or SOP data via Instancing toggle on Geometry COMP.
- USD / FBX Import
- TD 2022+ supports USD scene import. FBX and Alembic for animated geometry. Enables integration with Blender, Houdini, and Maya pipelines.
- OSC
- Open Sound Control. Flexible message protocol over UDP. Map OSC messages to TD parameters for control from phones, tablets, or external software.
- Derivative Forum
- TouchDesigner's primary community resource at derivative.ca/forum. Search before posting — most questions answered in existing threads with file examples.