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The Sound object defines a sound emission point for the Spatial Audio chop. Multiple sound sources can be mixed by one Spatial Audio chop to create stereo or surround sound, with special effects like the doppler effect, volume loss over distance, obstacle interference, atmospheric filtering and positional audio.
To setup a Spatial Audio scene, one or more Sound objects should be used to emit sound. At least one microphone is needed to capture the sound. A SpatialAudio chop is needed to render the sound. If any obstacles or filters are used, at least one Acoustic chop is needed to design the spectrum filter.
Moving Sound and Microphone objects around will produce variations in pitch and volume, especially if either object is directional. Setting up a directional microphone or sound object is much like setting up a directional light.
The transform of objects are also determined by the presence of any added node properties.
The left menu chooses the order in which transforms are applied (for example, scale, then rotate, then translate). This can change the position and orientation of the object, in the same way that going a block and turning east takes you to a different place than turning east and then going a block.
The right menu chooses the order in which to rotate around the X, Y, and Z axes. Certain orders can make character joint transforms easier to use, depending on the character.
Translation along XYZ axes.
Degrees rotation about XYZ axes.
Non-uniform scaling about XYZ axes.
Local origin of the object. See also setting the pivot point .
Scale the object uniformly along all three axes.
This menu contains options for manipulating the pre-transform values. The pre-transform is an internal transform that is applied prior to the regular transform parameters. This allows you to change the frame of reference for the translate, rotate, scale parameter values below without changing the overall transform.
This reverts the translate, rotate, scale parameters to their default values while maintaining the same overall transform.
This sets the translate parameter to (0, 0, 0) while maintaining the same overall transform.
This sets the rotate parameter to (0, 0, 0) while maintaining the same overall transform.
This sets the scale parameter to (1, 1, 1) while maintaining the same overall transform.
This removes the pre-transform by setting the translate, rotate, and scale parameters in order to maintain the same overall transform. Note that if there were shears in the pre-transform, it can not be completely removed.
This completely removes the pre-transform without changing any parameters. This will change the overall transform of the object if there are any non-default values in the translate, rotate, and scale parameters.
Keep Position When Parenting
When the object is re-parented, maintain its current world position by changing the object’s transform parameters.
When the object is being transformed, maintain the current world transforms of its children by changing their transform parameters.
Enable Constraints Network on the object.
Path to a CHOP Constraints Network. See also creating constraints.
You can you use the Constraints drop down button to activate one of the Constraints Shelf Tool. If you do so, the first pick session is filled automatically by nodes selected in the parameter panel.
Turns the sound source on (if greater than zero) or off.
The volume of the sound source.
If off, the sound source is non-directional and emits sound equally in all directions. Otherwise, the sound source is directional and pointed down the negative Z axis. The emission cone and outer cone parameters determine the field of emission. Any sound emitted from within the emission cone have a gain defined by the volume (above). Any sound emitted outside the outer cone have a gain defined by the outer volume parameter (below). Any sound emitted between the recording cone and the outer cone have a gain that is interpolated between the two volumes.
Defines the angle of the emission cone, measured from the Z axis to the edge of the cone. Setting this to 180 degrees will make a non-directional sound source.
Defines the dropoff region from the emission cone to the outer cone. If the emission cone is set to 60 degrees and the outer cone is set to 20 degrees, any sounds emitted from more than 80 degrees off the Z axis will fall outside the outer cone.
Sets the interpolation type for the dropoff from the emission cone volume to the outer volume.
Increases or decreases the rate of dropoff.
The gain that is applied to any sounds coming from outside the outer cone.
Specifies the CHOP that contains the audio that this Sound object is emitted. Only one audio track can be emitted; if there is more than one audio track in the CHOP, the first one is used.
Set Wireframe Color
Use the specified wireframe color
The display color of the object
Viewport Selecting Enabled
Object is capable of being picked in the viewport.
Script to run when the object is picked in the viewport. See select scripts .
Cache Object Transform
Caches object transforms once Houdini calculates them. This is especially useful for objects whose world space position is expensive to calculate (such as Sticky objects), and objects at the end of long parenting chains (such as Bones). This option is turned on by default for Sticky and Bone objects.
See the OBJ Caching section of the Houdini Preferences window for how to control the size of the object transform cache.