Rigid Body Collection
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Create panel (Helpers) reactor RBCollection

Animation menu reactor Create Object Rigid Body Collection

reactor toolbar (Create Rigid Body Collection)

The Rigid Body Collection is a reactor helper object that acts as a container for rigid bodies. Once you have added a Rigid Body Collection to your scene, you can add any valid rigid bodies in the scene to the collection. You can find out more about rigid bodies in the Rigid Body Basics section.

When you run the simulation, reactor examines the Rigid Body Collections in the scene and, provided the collections are not disabled, adds the rigid bodies they contain to the simulation.

At a lower level, a collection also allows you to choose the mathematical method to be used for solving the rigid body behaviors for its member bodies.


To create and use a Rigid Body Collection:

  1. Choose any of the above commands, and then click in any viewport to add the Rigid Body Collection.
    NoteThe icon’s position has no effect on the collection’s behavior.

    The collection icon is added to the scene. You can add rigid bodies to the collection in two ways: by picking or by using a selection list.

  2. Add objects to the collection using either (or both) of these methods:
    • On the RB Collection Properties rollout, click the Pick button, and then in the viewport, click an object to add.
    • On the RB Collection Properties rollout, click the Add button, and then use the Select Rigid Bodies dialog to specify one or more objects to add.

To create a collection and add bodies in a single step:

  1. Create and select the objects to add to the collection.
  2. Create the collection using the reactor toolbar, reactor menu, or quad menu. reactor instantly places the collection in the scene and adds the selected objects to the collection.


RB Collection Properties rollout


Cause the objects in the Rigid Bodies list to display momentarily in the viewports as if selected.

Rigid Bodies

Lists the names of the objects in the Rigid Body Collection.


Lets you add an object to the Rigid Body Collection. Click this button, then in the viewport move the cursor over the object you would like to add to the collection. If the object can be used as a rigid body the cursor will change from an arrow to a cross and you can select the object to add it to the collection.


Lets you add one or more objects from the scene to the collection. Click the button to open the Select Rigid Bodies dialog. Make a selection in the provided list, and then click the Select button to add the objects to the collection.


Lets you remove objects from the collection. In the rigid bodies list, select the bodies you would like to remove from the collection and click this button.


When on, the collection and the bodies it contains are not added to the simulation.

Advanced rollout

ODE Solver

Lets you choose the method by which reactor simulates the collection:

  • EulerThe collection calculates the behavior for its rigid bodies using an Euler ODE (Ordinary Differential Equation) solver. Euler is a fast method that provides good results in most cases.
  • Runge-KuttaThis method is more accurate in some cases but requires more computation. Use Runge-Kutta if you have many object connected using simple constraints like springs or dashpots, because those kind of systems can easily become unstable.
Reset Default Values

Sets values for the collection to their defaults. In this instance, it sets the ODE Solver back to its default value.