Playing Back the Rigid Body Simulation
Before you play a simulation, you should make sure that you have set up the time information for it in the environment’s Simulation Time Control. To do this, you set the duration of the simulation, select the playback mode (standard, live, or interactive), and you may choose to cache the simulation to create an action source for it.
To play the simulation
• Click the Play button in the playback controls below the timeline.
The simulation is calculated starting from the first frame of the simulation according to the Time Reference settings in the Simulation Time Control property editor (see Setting Up the Simulation’s Frame Range below).
• To calculate the whole simulation quickly, go to the last frame of the simulation.
• While the simulation is being calculated, you can stop it at any point by clicking Cancel on the progress bar.
Viewing Simulation Information
You can display the simulation/cache information of the current simulation environment in the lower-left corner of a viewport. The information shown is the start and end of the simulation, the last frame that has been cached, whether the cache is on, and whether the cache is locked.
To view the simulation/caching information
Do either of the following:
• Activate a viewport, then click the Toggle Simulation Info button in the Simulation Time Control property editor to turn the information on or off.
or
1. Choose Visibility Options (or press Shift+s) from the eye icon menu in a viewport.
2. In the Camera Visibility property editor, click the Stats tab and select Show Simulation Info.
Setting Up the Simulation’s Frame Range
When you play a simulation, it uses the settings you’ve defined in the environment’s Simulation Time Control property editor. The settings are taken from the scene’s timeline information by default, but you can modify them as you like.
To set the simulation’s time
1. Choose Modify > Rigid Body > Edit Simulation Properties to open the Simulation Time Control property page for the current simulation environment.
You can also select the Curr. Envir. or Environments scope in the explorer, then click the Simulation Time Control icon to open this property editor.
To set the simulation’s range of frames
• Set the simulation’s Offset, which is the number of frames that the simulation is offset from the scene’s first frame.
• Set the simulation’s Duration, which is the number of frames over which the simulation is calculated.
• Click the Copy to Scene button to copy the Offset and Duration values to the scene’s timeline.
To use the scene’s timeline settings for the simulation’s range
• Do either of the following:
- A quick way to set the simulation’s frame range is to click the Copy from Scene button. This copies the scene’s timeline values to the Offset and Duration values. Remember that if you change the timeline’s start or end frames, you will need to update the simulation’s frame range as well.
or
- To keep a link to the scene’s timeline start and end frames, select the Use start/end frame options. These set the Offset and Duration values to match the scene’s time. When you make a change to the scene timeline’s start or end frame, the changes are automatically reflected in the Offset and Duration values.
When the Use start/end frame options are active, you cannot directly change the Duration values.
Muting the Rigid Body Simulation
You can temporarily disable a rigid body simulation by muting its time control. This is useful if you have other animation or simulations in a scene but you don’t want to play the rigid body simulation.
To mute the rigid body simulation
• Open the environment’s Simulation Time Control property editor and deselect the Active option.
The way the rigid body simulation is updated depends on which play mode you are using: Live, Standard, or Interactive.
To select a play mode
1. Open the Simulation Time Control property editor.
2. Select an option from the Play Mode list: Standard, Live, or Interactive.
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When doing a final render of the scene and you are doing distributed rendering or using motion blur, you should turn on caching and use the Standard mode; otherwise, you can use Live mode for rendering as well. You cannot, however, see the effects of motion blur when using Interactive mode. |
Standard Mode
Standard mode plays the simulation from the first frame. If you change one of the elements in the simulation, the simulation is recomputed from the initial state at the next frame change. If you go to a previous frame (playing backwards), the simulation is not recomputed.
Standard mode calculates the simulation only when you go to a different frame, either by clicking the Play button below the timeline or moving the playback cursor.
Live Mode
Live mode plays the simulation, updating it at each frame with any change that you make. This mode allows you to play a simulation continuously for quick editing and tweaking. You can then view the effect of any modifications in real time.
Live mode is best when you play the simulation with looping on—this way you can tune parameters and immediately see what happens without restarting the simulation from its first frame. Any change you make to any elements within the rigid body simulation environment affects the simulation only from that point on: the simulation is not recalculated from the start.
As soon as you skip forward, the simulation is computed for the current frame from all of the intermediate frames.
When you drag the playback cursor forward in the timeline or click the Play button, the simulation is updated to the current frame.
Interactive Mode
Interactive mode updates the simulation as you interact with a rigid body. This is similar to how quick stretch works when you select a quick-stretched object and translate it. This is useful for quickly trying out different variations for the simulation without having to play it back. For example, you can go to a specific frame and then modify a rigid body (such as changing its position or rotation) to quickly test it the resulting simulation.
For spring-based control objects in rigs (see Spring Operators for Tail, Ear, and Belly Rig Controls [ Character Animation ]), you need to select this mode to simulate their movement (this is their default setting).
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