Preview & Animation Rollout
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Utility panel reactor Preview & Animation rollout

This rollout lets you run and preview your reactor simulation, as well as specifying timing parameters for the simulation.


Start Frame

When creating a world to be simulated or previewed, reactor needs to access the objects in 3ds Max at a fixed point in time. This parameter defines this point in time (in 3ds Max frames). Initial shapes, positions and velocities are taken from the actual shapes, positions and velocities of the objects in the scene at this particular frame. When creating an animation, keyframes are created starting from this frame to the End Frame time.

End Frame

The last frame to simulate. When reactor creates an animation, it generates keyframes from the Start Frame time to this frame.


The number of frames for every keyframe that reactor creates (time step). For example, a value of 2 will create a keyframe every other frame. Increasing this value forces reactor to take bigger time steps, potentially reducing the accuracy of the simulation; you might need to then update the Substeps/Key setting accordingly (see following).


The number of reactor simulation substeps per keyframe (that is, per time step). The higher this value, the more accurate the simulation will be, although it will also require more computation to simulate. For information about time steps and substeps, see Time Steps.

Time Scale

This parameter maps between time in the simulation and time in 3ds Max. Changing the value lets you slow down or speed up the animation. Values less than 1.0 produce slow-motion animations, while values greater than 1.0 produce sped-up animations.

Create Animation

Runs the simulation and creates keyframes, starting at Start Frame and ending at End Frame.

Update Viewports

When on, updates the scene in the viewports as the animation is created.

Create List/Layer

When on, creates a List controller (unless one is already present) for the position and rotation tracks of those rigid bodies using Position/Rotation/Scale transform controllers. A new subcontroller is added to the List controller to hold the keys created by reactor. This new controller is weighted to 100, while the previous controllers are weighted to 0. In the special case of rigid bodies belonging to a character studio Biped, a new biped layer is created every time a reactor animation is generated.

Preview Animation

Previews the simulated scene in the Preview Window.