TouchDesigner

Personal knowledge base for rapid re‑entry into TouchDesigner after long breaks.

TouchDesigner uses node‑based workflows where data flows through operators (OPs) that cook when needed.

• Official Website

• Interactive and Immersive HQ Tutorial channel

• O|I toggle: Enables/disables cooking globally (useful for heavy networks).
• Perform Mode: Toggle with F1. Used to run the system fullscreen. ESC returns to editing mode.
• Palette: Contains ready‑made components; double‑click to inspect internal networks.
• Operator Snippets: Help → Operator Snippets shows practical examples for most OPs.
• ■ button : Open viewer (floating window) while keeping Network Editor open

Buttons in the bottom right of OPs

• ♦: Toggle Active (Allows panning/zooming inside the viewer without affecting the OP’s output)
• ●: Toggle Display in background

• Panes can be split using ALT + [ (vertical) or ALT + ] (horizontal).
• The ▼ button on each pane opens more panes; the ↓ menu switches pane types (Network Editor, Geometry View, etc.).
• ALT + Z: Close pane under mouse.

• Left Click + drag: Move operator or pan when clicking empty space.
• Right Click + drag: Selection box.
• Mouse Wheel: Zoom.

(Shortcuts only work with the cursor in the Network Editor, and are case sensitive - careful with CAPS LOCK).

• TAB: Open Operator Create Menu (type in name to highlight)
• I: Dive inside a network. (also mouse wheel on it but clunky)
• U: Move up a level.
• H: Frame/home network.
• P: Toggle Parameters window.

• TOP: TEXTURE OPERATOR - Purple - 2D raster graphics
• CHOP: CHANNEL OPERATOR - Green - channels, numeric/time data, signal, communication,
• DAT: DATA OPERATOR - Pink - tables, strings, scripting
• SOP: SURFACE OPERATOR - Blue - Procedural 3D geometry
• COMP: COMPONENT OPERATOR - Grey - components, UI, 3D rendering
• MAT: MATERIAL OPERATOR - Yellow - materials, shaders

Dark-colored OPs are generators.

• Data flows left → right.
• Cooking occurs when dependent OPs need updated data.
• Animated noodles = cooking
• Static noodles = cached.
• Heavy cooking sources:
  • Full-res TOP chains
  • CHOPs with large sample counts
  • SOP deformers

Use nulls, selects, Resolution TOP, and Cache Select to avoid unnecessary cooking.

• Networks behave like Unix-style folders.
• Path bar shows current location.
• Double-click a COMP to see its internal network.

• Display flag = viewer preview.
• Render flag = included in rendering.
• Middle-click → info popup.
• “?” in parameter window → operator wiki page.

• Middle-click/hold a parameter to adjust increments. Slide Left / Right to increase/decrease
  • Use on name of parameter to affect all values simultaneously.
• Drag CHOP channels into parameters:
  • CHOP references
  • Export bindings
• Drag CHOPs onto TOPs to convert.

TouchDesigner mixes several structures:

• TOPs → images (resolution-dependent)
• CHOPs → channels (sample rate–based)
• SOPs → points/geometry
• DATs → strings/tables

Important relationships:

• Instancing: SOP point count = CHOP sample count.
• CHOPs depend on FPS; TOPs depend on resolution.

• SOPs exist on CPU → piped into Geometry COMP.
• Camera and Light COMPs define render scene.
• Render TOP outputs a 2D texture.

• Inputs:

– Camera

  – Geometry COMPs  
  – Lights  
* End with a null TOP for stability.

• Keep one object per Geometry COMP when possible.
• Cameras operate like standard 3D transforms.
• Light types: Point, Spot, Directional.

• SOP chain → Null SOP → Geometry COMP
• Geometry → Render TOP → Composite/FX
• Use Select TOPs to inspect interim results.

• Main operator for projection/output.
• Settings:

– Monitor

  – Opening Size  
  – Borders  

• Enter using F1.
• Layouts may scale differently; test UI carefully.

• Use nulls at key checkpoints.
• Reference nulls elsewhere to avoid breaking chains.

• Extract channels with Select CHOPs.
• Organizes complex CHOP data streams.

• Drop resolution early to speed up heavy FX.
• Increase resolution at end of chain.

• absTime.frame → integer frame counter.
• absTime.seconds → time in seconds.
• me.digits → returns numeric suffix of OP name.

• Cache TOP stores multiple frames (heavy on VRAM).
• Cache Select references those frames without extra memory.
• Pair Cache + Reorder TOP for temporal RGB shifting.

• Match SOP points to CHOP samples.
• Enable instancing in Geometry COMP → Instance tab.
• Position, scale, rotation via CHOP channels.

• Outputs motion vectors (R = X velocity, G = Y velocity).
• Useful for simulations, particles, reactive systems.

• Feedback TOP + Transform + Composite.
• Use Resolution TOP to prevent GPU overload.

• CHOP Trail for numeric history.
• TOP composite trails for visual streaks.

• Composite TOP blends layers using Over, Add, Screen, etc.

• LFO, Noise, Trigger CHOPs for dynamic control.
• Export or reference in parameters.

• Common structure:

Source → Level → Blur → Edge → Composite → Null

• Keep heavy FX at low resolution.

• Repetition of simple forms builds complex visuals.
• Overlapping translucent layers enrich motion and depth.
• Vary timing, resolution, and color to create dynamic energy.

Rendering is done in a Render TOP.

Basic setup involves the 3D COMPS Cameras, Geometry and Light to bring the SOP chain operating on the CPU to the Rendering pipeline operating on the GPU and rasterize the content.

Add In SOPS in the Geometry op to send a chain of SOPS into it.

The display and render flags tell the rest of the network whether the node should be used in the rendering process and displayed in the viewer.

You can also take the output of your last (preferably null) operator in the SOP chain and right click > COMP > Geometry to automate a lot of the process.

You can put multiple things in a geometry comp with the display flag ON but it's best practice to keep just one item per geometry to have a cleaner network.

This operator calculates the motion vectors inside a video stream and codes it to the Red and Green channels.

This converts video streams into usable data for interactivity.

The data can be plugged into particle systems, fluid systems or any other creative content that accept data as input to react upon.

Output is done by using the Window COMP.

You can open as a separate window or in perform mode.

Tweak the Monitor, Opening Size and Toggle the Borders parameters.

Texturing is done with MAT operators and by sending things into the Color map property.

When creating a network of nodes, add null operators at strategic checkpoints. This way you can reference these null “checkpoints” everywhere else in your project and if anything has to change prior to the checkpoint the reference is still valid.

TOPs have a display flag at the bottom right which can be turned on to toggle a preview in the background of the network editor.

Use Select CHOPs to extract different channels from your other CHOPS to use them in the network.

• Select the CHOP and toggle the display with the + in the bottom right
• Select the TOP to link to parameter
• Drag & drop from the CHOP into the parameter
• Select Reference type (Most of the time it's CHOP Reference

You can also drag an entire CHOP into a CHOP to TOP operator to reference it.

COMP Buttons and sliders can be connected to Null operators to toggle them into run mode and handily display their output.

It's good practice to work in lower resolutions until you need to up the resolution with a Resolution TOP.

When using source loops into TOP Fx chains it's handy to pass them through a Resolution TOP and lower them down to half res to improve performance.

• absTime.frame will use the frame count to increment the parameter this expression is used on. Use math expression behind such as * 0.5 to slow down (or speed up)
• absTime.seconds like the above but slower
• me.digits will return the digit (auto incremented) in the operator name. You can associate it with a math expression such as * -5 to automatically increment or decrement a parameter as you copy/paste (useful for Cache Select building a trail effect for example).

Be wary of the frame count when using the Cache TOP as it is essentially what uses the most GPU memory.

It's best to use a Cache Select TOP rather than using the Output Index of the Cache TOP. They will have very small cook times and be totally free in terms of GPU memory as they will reference the images that are already in memory through the Cache TOP.

Use the Reorder top in conjunction with Cache and Cache select to create some nice RGB trailing effects

When working with instancing take care that the length match. For example if your SOP null has 40 points, then the CHOP you use on it should have 40 samples.

Instancing is done in the Geometry Comp under the tab of the same name. Reference another SOP in there and play around with the points.

Repetition of small processes (as basic as drawing a circle at every point of a circle) can make some very rich designs.

Overlapping content also enriches designs.