COMPs: Components

Component Operators — COMPs — are the structural layer of TouchDesigner. While TOPs, CHOPs, SOPs, and DATs all process specific data types, COMPs are organisational: they are containers that hold networks of other operators, 3D scene objects that exist in world space, and interface elements that face the user. Every TouchDesigner project is fundamentally a hierarchy of COMPs.

The Base COMP

A Base COMP is the simplest container. Double-click it to enter its internal network, where you can place any operators you like. From outside, the Base COMP is just a labelled box. This is how you organise large projects — break complex subsystems (audio analysis, scene rendering, UI) into separate Base COMPs and name them clearly.

Base COMPs can expose custom parameters using the Custom Parameters dialog (Edit > Custom Parameters). This lets you build a kind of “module interface” — the internals are hidden inside the Base COMP, but the key parameters are surfaced on the outside. Any operator inside can read those parameters with parent().par.myParam.

The Container COMP

A Container COMP is designed for building user interfaces and panels. It has a resolution parameter and renders its contents as a 2D panel — buttons, sliders, text overlays. When you connect a Container COMP to a Window COMP, it acts as the UI layer of your project.

Inside a Container COMP you can place Button COMPs, Slider COMPs, and Text COMPs. Each generates a CHOP output with its current value. Nest Container COMPs for complex layouts: a master container holding rows of smaller containers for distinct UI zones.

The Geo COMP

The Geo COMP is the core 3D scene object. It has two main jobs:

1. It holds a SOP network inside it. The SOPs define the shape of the geometry.
2. It carries a Material parameter that assigns a MAT to the geometry for rendering.

On its Transform page, you set the object’s position, rotation, and scale in world space. These parameters can be driven by CHOP exports, making it straightforward to animate geometry positionally without touching anything inside the Geo COMP.

The Geo COMP also has a Render parameter (on by default) and a Shadow parameter. To hide geometry in a render without deleting it, uncheck Render.

The Camera COMP

A Camera COMP defines the viewpoint from which the scene is rendered. Its critical parameters:

• Translate / Rotate: The camera’s world-space position and orientation. Translate Z to –5 to pull back from the origin; Rotate X to –15 to tilt slightly downward.
• Projection: Perspective (the standard real-world camera perspective) or Orthographic (no perspective foreshortening — great for flat, graphic looks).
• Field of View: In Perspective mode, a lower FOV (28°) looks telephoto and compresses depth; a higher FOV (90°) looks wide-angle and exaggerates depth.
• Near / Far Clip: The depth range within which objects are rendered. Objects outside this range are clipped.

The Object CHOP can extract the Camera COMP’s world-space position and rotation as CHOP channels, useful if you want to drive other parameters relative to camera movement.

Light COMPs

Light COMPs illuminate Geo COMPs in the render. TouchDesigner offers four light types, set via the Light Type parameter:

• Ambient: Illuminates all surfaces equally regardless of direction. Use for a base brightness floor to avoid pitch-black shadows.
• Point: A light that radiates in all directions from a single point in world space. Good for simulating bulbs and sparkles.
• Directional: Parallel light rays, like sunlight. Direction is determined by the Light COMP’s rotation. No falloff with distance.
• Spot: A cone of light from a point. Set Cone Angle and Cone Delta to control the spread and edge softness.

Each Light COMP has Diffuse Colour and Specular Colour parameters. Separate them: a warm diffuse (orange-white) and cooler specular (blue-white) immediately makes a scene look more dimensional. The Attenuation parameters (Constant, Linear, Quadratic) control how quickly point and spot lights fall off with distance.

The Render TOP

The Render TOP is where 3D becomes 2D again. It is the bridge between the SOP/COMP world and the TOP world. Key parameters:

• Camera: Which Camera COMP to render from.
• Render: A list of Geo COMPs to include in the render. You can add and remove Geo COMPs from the list without rewiring anything.
• Lights: Optionally override which lights illuminate the scene. If left empty, all Light COMPs in the network are included automatically.
• Background Color: The colour of empty space behind all geometry.
• Multisample: Antialiasing quality. Set to 4× for smooth edges with acceptable performance cost.
• Depth Buffer: Enable for correct occlusion (closer objects obscuring farther ones).

The output of the Render TOP is a regular RGBA texture that you pipe into whatever TOP network handles your colour grading and output.

The Object CHOP

The Object CHOP extracts positional and orientation data from scene objects and outputs them as CHOP channels. Point its Object parameter at any COMP and select which attributes to extract: tx, ty, tz (translation), rx, ry, rz (rotation), or a specific point on the object’s bounding box.

This is particularly useful for making camera-relative effects — extracting a Geo COMP’s screen-space position to drive an overlay TOP, for example.

Building a Complete 3D Scene

Here is the full minimal scene:

1. Place a Geo COMP in your main network. Double-click to enter it. Inside, place a Sphere SOP with Rows 40, Columns 40, and Radius 1.0. Return to the parent network (press U or click the path breadcrumb).

2. In the Geo COMP’s parameter dialog, set the Material parameter to a Phong MAT you create nearby. In the Phong MAT, set Diffuse colour to a saturated teal (0.1, 0.7, 0.6) and Specular to white, Shininess 60.

3. Place a Camera COMP. Set Translate to (0, 1, –5) and Rotate X to –10. Leave Projection as Perspective, Field of View at 45.

4. Place a Light COMP. Set Light Type to Directional. Set Rotate X to –45 and Rotate Y to 30 so the light falls diagonally across the sphere. Set Diffuse Colour to a warm white (1.0, 0.95, 0.85).

5. Place a second Light COMP for fill. Set Type to Ambient, Diffuse Colour to a dark blue (0.05, 0.05, 0.2) for a subtle cool shadow fill.

6. Place a Render TOP. Set Camera to camera1, add geo1 to the Render list. Set Background Color to near-black (0.02, 0.02, 0.02). Set Multisample to 4.

7. Connect the Render TOP to a Null TOP named OUT.

You now have a lit, rendered sphere. Add an LFO CHOP at Rate 0.2 and export its channel to the Geo COMP’s Rotate Y parameter — the sphere spins continuously. This is the scaffold for every 3D installation you will build.

COMPs give your project structure, scalability, and the ability to share reusable modules. As your projects grow in complexity, well-named COMPs are what keep them navigable.