Generating motion from existing sounds

Since many motion effects will be linked to audio events, such as gunshots, road vibrations, explosions, and so on, you can generate motion data directly from the existing sounds and music objects in your project. In this case, Wwise simply takes the audio signal, extracts the low-frequency components and then resamples this part of the signal to give a convincing motion effect. Although this method requires very little effort on the part of the designer and developer and is perfect for motion that is synced with audio, it does have the following disadvantages:

Less control over the type of motion that is created.
More CPU intensive as the audio signal must be filtered and resampled at run-time to create the motion data.
Does not handle cases where motion is not related to audio.

Despite these disadvantages, there are situations where this method can be useful. For example, this method is perfect for creating prototypes of motion in your game. When the prototypes are completed and approved, you can then decide whether to go on to create specific motion objects that allow for more control.

Before generating motion from existing sounds, you should be aware of the following:

The removal of the DC offset from the original audio source will alter the motion output.
The motion output will feel different on each platform's controller due to differences in the physical motors' power, top speed, and weight.

Specifying output routing for motion

If you plan to generate motion data from an existing audio source or a motion source, you need to first decide through which motion bus it will be routed. Motion data is different than audio data, and requires a separate hierarchy of busses through which the motion data can be routed. You can create this separate hierarchy in the Master-Mixer Hierarchy by creating a new master bus and assigning the Wwise Motion device to it. For more information on creating a motion bus hierarchy, refer to Building an output structure for motion.

To specify the output routing for a motion-only source:

Load a top-level object into the Property Editor.
In the Output Bus group, click the Browse button (...).
The Project Explorer - Browser opens.
Select a bus that is under a motion-enabled master bus.
Click OK.
The motion data generated from the current object and any child objects below it is now routed through the selected bus.

To specify the output routing for motion, on an audio source:

Load a top-level object into the Property Editor.
In the User-defined Auxiliary Sends group, click the Browse button (...).
The Project Explorer - Browser opens.
Select an Auxiliary Bus that is under a motion-enabled master bus.
Click OK.
The motion data generated from the current object, and any child objects below it, is now routed through the selected bus.

When setting up your routing, make sure to also take note of the bus configuration of the Master Bus, and any Buses you create. For example, most Wwise Motion Audio Devices will use an Anonymous 2-channel Master Bus, such that each channel of the audio is associated with a physical motor, as opposed to a Stereo 2-channel Master Bus. In order to control which channel the audio goes to, you may have to provide a 2-channel wave file as the audio source, even if only one channel has non-zero data. Alternatively, if that is not practical, you can set a Bus in the routing path to use a Stereo 2-channel output configuration, and use the Bus's speaker panning to redirect audio to the desired channel.

	Note
	Some Wwise Motion Audio Devices may use alternative bus configurations, such as Stereo 2-channel, Anonymous 4-channel, or others, and may require different setups for channel routing. Refer to Integrating Wwise Motion for information about supported devices and their respective channel configurations.

Shaping the motion signal from audio

Motion devices can only create low frequencies, so you may need to reduce or filter the high frequencies from the audio source. The resulting signal may also need amplification to be felt at a proper strength. Given that the audio signal is transmitted to a motion bus through a Send to an Auxiliary Bus, you can use the regular tools provided by the Send feature.

	Caution
	Do not use high-pass filters on motion objects. Motion devices only produce low frequencies, so any high-pass filter effectively mutes the motion.

To filter out high frequencies:

Load a motion related Auxiliary Bus into the Property Editor.
In the Output Bus group, modify the Low Pass filter value to set the cutoff frequency that will be used to generate the motion signal.

To boost or reduce the generated motion signal:

Load an audio structure into the Property Editor.
In the User-defined Auxiliary Sends group, modify the Volume value to either amplify or attenuate the motion signal.

Additionally, you could use an Effect on the Auxiliary Bus, such as an EQ, to boost or reduce some frequency band.

	Note
	To test the intensity of the motion effect in Wwise, you must connect a motion device to your workstation and then play back the Wwise object.

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