Yusuf's Thoughts

COMP - Components

4 min read

COMP - Components

COMPs are the family that holds other networks. Every other operator family stays in its own column of the network; COMPs are the wrappers that group ops together, give them a 3D transform, host a UI panel, or run a sub-process. They’re the structural backbone of any project bigger than a sketch.

Three Sub-Families

Sub-familyWhat it isExamples
Object COMPs”A subset of all Components, used to create and render 3D scenes.” Each carries a 3D transform.Geometry, Camera, Light, Ambient Light, Environment Light, Bone, Null, Handle, FBX, USD
Panel COMPs”Used to create custom interactive 2D control panels and user interfaces (also called Panels).”Container, Widget, Button, Slider, Field, Text, List, Table, OP Viewer, Parameter, Select
Misc / UtilityEverything else: logic groupings, animation, replication, time, sub-process isolation.Base, Animation, Replicator, Time, Engine

Container vs Base (the one to memorize)

ChoiceWhen to use
Container COMP (Panel)Anything you want to render as a UI panel: a window of buttons, sliders, an inspector. Has Width/Height and a panel TOP.
Base COMPPure logic grouping. The wiki: “no panel parameters and no 3D object parameters… a component that has no panel associated with it, nor any 3D.” Use it for utility modules.

Picking Base for a “fold this Python and CHOP logic away” group keeps the parameter dialog clean (no irrelevant Panel parameters), and avoids the cooking cost of a Container with a visible panel.

Custom Parameters

Any COMP can have custom parameters: knobs you add to the wrapper, exposed at the COMP level. Inside the COMP, internal nodes bind to those parameters, so the wrapper acts as a clean module interface. This is the foundation of every reusable .tox. Full details on the Ch 04 page: Custom Parameters.

Nesting and Navigation

ActionHow
Enter a COMPClick the selected COMP, press i, or scroll-wheel into it
Exit upward one levelPress u, or scroll-wheel out
Pass data across the COMP boundaryIn CHOP/TOP/SOP/DAT inside the COMP, Out CHOP/TOP/SOP/DAT
Reach into a parent or grandparentparent(), parent(2), or define Parent Shortcuts on the COMP
Reach into a fixed internal nodeiop (Internal Operator) shortcut declared on the COMP

See The op and me objects for the Python side of these.

Building a Reusable Module

The standard recipe:

1. Group the network: select the nodes, RMB → Collapse Selected → Base COMP
2. Customize: RMB → Customize Component → add custom parameters
3. Bind: inside the COMP, set internal node parameters to Bind mode against the new custom parameters
4. (Optional) Add a panel: drop a Container COMP inside, add Sliders/Buttons bound to the same custom params
5. Save: RMB the wrapper → Save Component .tox

Now anyone (including future you) can drop the .tox in and get a clean parameter surface without touching internals. See Modular Design and Toxes for the full pattern, and Container and Widgets for the panel side.

Common Gotchas

  • Container COMPs cook when visible. A panel that’s currently displayed is itself a cook request, even if the value behind it didn’t change. Hide panels you’re not watching, or toggle the Cooking Flag on the wrapper.
  • Replicator rebuilds wholesale. Changing the source DAT regenerates every replicated child from scratch; in-flight state is lost. Don’t use it for things that need persistent state.
  • Custom parameter name collisions. Custom parameters live in the same namespace as built-ins on the COMP. Adding a custom Width to a Container quietly shadows the built-in. Capitalize and prefix to be safe.
  • Base vs Container at save time. A Container COMP saved as a .tox carries panel parameters. Strip them down to a Base before saving if the module is logic-only.

(y-) Next Page: Geo COMP

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