The classic Button object in Grasshopper trigger two recomputation when clicked. One is from False to True, while the following is True to False. However, the latter behavior is sometimes undesirable, and will clear some error messages. It is why many third-party libraries recommend a toggle instead of a button to control an immediate action.

True-only button provides a button object that only emit once when clicked.

How to use this component?

  • The component is listed under Pancake tab, Logic

  • Or you can find it via double-clicking

The exact behavior of True-only button (as of 1.3.0.0)

  • When clicked as figure (a), true-only button emits true, expires all downstream components and cause them to recomputation.

  • When released as figure (b), the button emits false and clear all recipient component, without causing a recomputation.

  • Then if you change other input as figure (c), for example, changing 1 to 2, the downstream component will pull data from the button (because it is cleared), which is false.

Behavior of True-only button
How classic button and true-only button work after 20 clicks. Counter component comes from Kangaroo 1.

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