Real-time playback and simulation don’t work together because the results at any frame in a simulation rely on the previous frame.
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.
For information on caching, see ICE Caching.
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 Playback Range below).
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Real-time playback and simulation don’t work together because the results at any frame in a simulation rely on the previous frame. |
• To stop the simulation playback, press the Down Arrow key or click the Play button again.
• To resume playback from the current, press the Up Arrow key or middle-click the Play button.
For more information on the standard playback controls, see Using the Playback Controls.
• To calculate the whole simulation quickly, go to the last frame of the simulation. Each frame of the simulation is calculated without having to play it.
• While the simulation is being calculated, you can stop it at any point by clicking Cancel on the progress bar.
Setting Up the Simulation’s Playback 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.
Note that ICE particles are actually emitted only starting the second frame of the simulation frame range. For example, if the start frame of the simulation is set to 1, the simulation starts at that frame, but particles are not actually emitted until frame 2. If you want the particles to be emitted at frame 1, enter 0 as the Offset value (below).
See Simulation Time Control Property Editor [ Dynamics Properties ] for information on each of these options.
To automatically use the timeline’s values for the simulation range
1. Select the Curr. Envir. or Environments scope in the explorer.
2. Click the Simulation Time Control icon in the explorer to open its property editor.
3. Select the Use start frame and Use end frame options to automatically use and stay linked to the scene’s timeline (start and end frames) settings for the simulation’s range. This way, if you change the timeline’s settings, the simulation frame range follows suit.
The Use start/end frame options set the Offset and Duration values to match the scene’s time, so when you make a change to the scene timeline’s start or end frame, the change is automatically reflected in the Offset and Duration values.
To offset the simulation’s time
1. Open the Simulation Time Control property editor.
2. Deselect the Use start frame option so that the Offset text box is enabled; otherwise, the start frame on the scene’s timeline is automatically used.
3. Set the Offset value, which is the number of frames that the simulation is offset from the scene’s first frame.
For example, if the first frame of the scene is frame 1 and you want the simulation to start 20 frames after the scene’s first frame, enter 21 here.
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You can quickly copy the Offset and Duration values to the scene’s start and end frame values by clicking the Copy to from Timeline buttons, or do the opposite with the Copy from Timeline button. Remember that if you change the timeline’s start or end frames, you will need to update the simulation’s frame range as well. |
To set the simulation’s duration
1. Open the Simulation Time Control property editor.
2. Deselect the Use end frame option so that the Duration text box is enabled; otherwise, the end frame on the scene’s timeline is automatically used.
3. Set the Duration value, which is the number of frames over which the simulation is calculated.
The way in which the ICE 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.
• Live mode plays the simulation, updating it at each frame with any change that you make. This is the default mode for ICE simulations. 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.
• Standard mode plays the simulation from the first frame. It calculates the simulation only when you go forward to a different frame. If you change one of the elements in the simulation, the simulation is recomputed from the initial state at the next frame change.
• 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.
See Simulation Time Control Property Editor [ Dynamics Properties ] for more information on each of these options.
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If you want to scrub and play the simulation backwards, you need to cache it into a file—see ICE Simulation Caching for information. |
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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. |
Viewing ICE 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.
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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.
You can temporarily disable an ICE 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 ICE simulation.
To mute the ICE simulation
• Open the environment’s Simulation Time Control property editor and deselect the Active option.
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