Timer CHOP

The Timer CHOP is the most robust and accurate way to handle triggers, countdowns, and time-based events in TouchDesigner. It is significantly more reliable for complex logic than building your own counters.

Key Concepts

The Timer CHOP doesn’t just “count up.” It manages a state machine for a segment of time.

• Length: The duration the timer will run.
• Segments: You can have the timer run through an array of different times (e.g., a 5-second intro, a 10-second main sequence, a 2-second outro). This is driven by an attached DAT table.
• Initialize / Start / Initialize Start:
  • Initialize: Resets the timer to 0 but does not play it.
  • Start: Begins playback.
  • Initialize Start: Does both simultaneously.

Outputs

The power of the Timer CHOP lies in what it outputs automatically. When you connect it to a Null CHOP, you’ll see several channels:

1. timer_fraction: Goes from 0.0 to 1.0 over the length of the timer. This is the most useful channel for driving animations or crossfades.
2. timer_seconds: The actual elapsed time.
3. running: Outputs a 1 when playing, 0 when stopped.
4. done: Fires a 1 exactly when the timer finishes. Perfect for triggering the next event in a sequence.

The Timer Callback DAT

When you create a Timer CHOP, it usually comes attached to a Text DAT full of Python callbacks (e.g., onInitialize, onStart, onDone).

This is incredibly powerful. You can write Python code that only executes when those specific events happen. For example, triggering a sound effect using onStart(), and loading a new level using onDone().

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(y-) Next Chapter: COMPs

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