Reactor System

Less than 1 minute

Reactor System

Entity reactors are used to establish relationships between entities so that when a source entity changes, related target entities are updated automatically.

Online Examples

Example	Description	Link
Basic Reactor	Use event listeners to implement entity response	Online Demo{target="_blank"}
Associative Dimension Reactor	Dimensions automatically follow source entity updates	Online Demo{target="_blank"}
Multi-Type Monitor Reactor	Monitor changes across multiple entity types	Online Demo{target="_blank"}
Constraint Reactor	Implement geometric constraints	Online Demo{target="_blank"}
Lifecycle Reactor	Monitor the full entity lifecycle	Online Demo{target="_blank"}

Overview

The reactor system is an advanced WebCAD feature used for:

Associative dimensions: dimensions update automatically when measured entities move
Geometric constraints: preserve relationships between entities
Parametric design: changing one entity triggers updates to related entities

Core API

Basic Reactor

const { EntityReactorManager } = vjcad;

// Register reactor
EntityReactorManager.register({
    sourceEntityId: sourceEntity.id,
    targetEntityId: targetEntity.id,
    onSourceModified: (source, target) => {
        // Update target entity when source entity changes
        target.move(source.center.x - target.center.x, 
                   source.center.y - target.center.y);
        Engine.regen();
    }
});

Associative Dimensions

// Create associative dimension
const dimension = new LinearDimensionEnt(/* ... */);
dimension.associateWith(lineEntity);  // Associate with line entity

// When the line moves, the dimension updates automatically

Use Cases

Associative dimensions: dimension annotations follow measured geometry
Equal-distance constraints: keep a fixed spacing between entities
Parallel constraints: preserve parallel relationships between lines
Concentric constraints: preserve concentric relationships between circles and arcs