Houdini 20.5 Nodes Geometry nodes

Smooth Motion geometry node

Smooths out unwanted noise in an animated input points or KineFX joint, skeleton, or MotionClip.

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Since 19.5

This node smooths out unwanted noise in a series of point attributes by applying a Butterworth Filter to remove frequencies that exceed a specified cut-off frequency.

Parameters

Input

Source Type

The animation source type for the first node input. This parameter is ignored if a second input is provided.

Skeleton

The first input is a KineFX skeleton.

Points

The first input is a general points input.

Group

The geometry group (joints or points) to apply the filter effect on.

Range

Clip Range

Read the frame range from the clipinfo detail attribute on the input geometry, or set a custom frame range.

Frame Range

The custom frame range of the animation. This parameter is only available when Clip Range is set to Custom Frame Range.

Use the action button on this parameter to populate the values from either the clipinfo detail attribute, the scene frame range, or the playback frame range.

Note

The Clip Range and Frame Range parameters are turned off and ignored if the MotionClip input is provided, in which case, the frame range from the MotionClip input is used.

Tip

The MotionClip inside this node will also be computed at the Frame Range, so if you want to affect only a portion of the full animation, set the frame range to the full clip range, and use the Blend parameters to apply the effect to only a specific portion of the clip.

Mode

Mode

Determines the Group point attributes to smooth.

Local Transform

The smoothing affects the localtransform on the specified Group points.

Other Attribute

The smoothing affects the custom attribute specified in the Attributes field.

Attributes

The point attributes on the Group to smooth.

You can specify your own custom attribute or select from a list. By default, Attributes is set to P transform.

This parameter is only available when Mode is set to Other Attribute.

Note

The following attribute types are supported: float, vector2, vector, 3x3 matrix, 4x4 matrix.

Tip

If the specified attribute is a vector describing an Euler rotation (for example, the result of running a cracktransform on a transformation matrix), try running it through an Euler filter first for better results (for example, cracking it using Attribute Transform Extract).

Alternatively, you can supply the transformation matrix to the node directly, and it will take care of the filtering for you.

Extract Transform

Determines the components of the matrix to affect for matrix attributes.

Transform Order

Sets the order of transformations that is used when cracking and rebuilding transformation matrices.

Rotation Order

Sets the order of rotations that is used when cracking and rebuilding transformation matrices.

Filter Properties

Type

The filter to use to smooth the input. Currently, only the Butterworth Filter is supported.

Order

The order of the filter. Determines how steeply the filter curve rolls off after the cutoff frequency. Higher orders correspond to a steeper roll off.

Cutoff Frequency

The cutoff frequency for the filter. Frequencies over this value are filtered out.

Blend

After smoothing has been applied, blends the selected Frame Range back to the original MotionClip using a Motion Clip Blend SOP node.

Blend Type

Sets the type of blending function to use.

Linear

Linear shape.

Ease in Ease out

Smooth on entry and exit.

Ease In

Smooth on entry.

Ease Out

Smooth on exit.

Bias

Specifies the bias percentage of the blend. A value of 0 biases toward the base, and a value of 1 biases toward the smoothed curve.

Blend In

Enable Blend

When turned on, the blend fades in from the start frame (weakest) to the end frame (strongest). When turned off, the smoothing will not fade out.

Start Frame

The frame at which to begin easing into the smoothing effect.

End Frame

The frame at which to finish easing into the smoothing effect.

Blend Out

Enable Blend

When turned on, the blend fades out from the end frame (strongest) to the start frame (weakest). When turned off, the smoothing will not fade out.

Start Frame

The frame at which to begin easing out of the smoothing effect.

End Frame

The frame at which to finish easing out of the smoothing effect.

Inputs

Skeleton

The input skeleton or points to smooth.

MotionClip

The animated input skeleton, in the form of a MotionClip. This input allows you to chain multiple Smooth Motion nodes together to avoid computing a new MotionClip for each node.

Outputs

Skeleton

The skeleton or points with the smoothing applied.

MotionClip

The skeleton with the smoothing applied, in the form of a MotionClip.

See also

Geometry nodes