Houdini 20.5 Nodes Geometry nodes

MotionClip geometry node

Converts a skeleton animation to a MotionClip.

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Since 18.5

This SOP takes as input a skeleton animation (for example, from FBX Animation Import), and evaluates and stores each frame of the input animation using the given frame range and sample rate.

The output consists of a list of packed primitives. The first primitive contains the skeleton topology evaluated at the given rest frame. The remaining primitives each represent a cached frame, and contain a list of points that represent the position of each joint. This output can be fed into MotionClip Evaluate to efficiently display a frame of the cached animation.

State

This viewport state allows you to visualize a MotionClip or its evaluated poses over time using a color ramp. It is available for every MotionClip SOP node that outputs a MotionClip.

MotionClip viewport state interaction

You can select individual joints from the current pose in the MotionClip viewport state. For the selected joints, you can then use the Evaluate Pose mode to view just the current pose, its selected joints, and the motion trails for those joints.

rFoot and lFoot joints selected, Mode = Evaluate Pose, Color = White to Red
MotionClip viewport state toolbar

Mode

Determines the MotionClip information that is displayed in the viewport.

MotionClip

Displays all the MotionClip’s poses.

Mode = MotionClip

Evaluate Pose

Displays a single MotionClip pose at the current time.

Mode = Evaluate Pose

Transparent MotionClip

When turned on, the MotionClip’s poses are displayed as fainter lines, making it easier to see the scene behind the MotionClip, as well as the evaluated pose.

Color

Applies the selected color ramp preset to the MotionClip’s visualization in the viewport. This color ramp helps to visualize changes to the MotionClip or individual poses over time.

Mode = Evaluate Pose, Color = White to Red

Extend Color

Determines how the poses outside of the MotionClip’s defined animation start and end range are visualized in the viewport.

Hold

Holds the color values at the ends of the range.

Mode = MotionClip, Color = Plasma, Extended Color = Hold

Gray

Poses outside the animation start and end range are colored gray.

Mode = MotionClip, Color = Plasma, Extended Color = Gray

Hide

Hides the poses outside the animation start and end range.

Mode = MotionClip, Color = Plasma, Extended Color = Hide

Parameters

MotionClip

Pack Inputs

When turned on, each input’s clip is placed into its own packed primitive. When turned off, the node only accepts a single input, and the clip is outputted directly.

Rest Frame

The clip’s clipinfo attribute is given by the input evaluated at this frame. If Use First Frame for Topology is turned off, this frame is also used for the topology of the MotionClip’s skeleton.

Sample Rate

The rate at which to sample the input animation.

Frame Range

The range of the input frames to grab. When turned off, the clipinfo detail attribute of the source is used.

Left End Behavior

Determines how the animation should behave when it is evaluated before the start of the MotionClip.

Clamp

The first and last poses are extended out indefinitely.

Loop

The animation repeats from the beginning.

Mirrored Loop

The animation repeats in reverse.

Right End Behavior

Determines how the animation should behave when it is evaluated after the end of the MotionClip.

Clamp

The first and last poses are extended out indefinitely.

Loop

The animation repeats from the beginning.

Mirrored Loop

The animation repeats in reverse.

Reload Method

Specifies whether the clip is automatically or manually reloaded when the input is changed.

Attributes to Store

A string matching the attributes you want to copy from the input into the MotionClip.

Tip

When creating a MotionClip, avoid storing any attributes that are expected to remain constant over the course of the animation, such as rest_transform and scaleinheritance. This will reduce the amount of storage required for the MotionClip and increase the efficency of other nodes that use MotionClips.

Recompute Local Transforms

When turned on, the localtransform attribute of each of the input frames are recomputed before the frame is stored.

This parameter should be turned on if the input has both world and local space transform attributes, and the local space transforms are not in sync with the world space transforms.

Use First Frame for Topology

When turned on, the first frame of each input animation is used as the topology of the skeleton for the corresponding MotionClip. When turned off, the pose evaluated at the Rest Frame is used as this topology.

Reload

Forces a reload of the input. This is useful when Reload Method is set to Manual.

Input Operators

Defines the order of the MotionClips when packing inputs.

Key Poses

Isolate Key Poses

When turned on, the key poses of the animation are identified by extracting the times at which a collection of channels are keyed.

Key Pose Attribute

When turned on, an integer primitive attribute is created on the MotionClips. The attribute is set to 1 on the identified key poses, and 0 otherwise. When turned off, only the identified key poses are added to the MotionClips.

Key Source

The source of the channels used to determine the key poses of the MotionClips.

Parameters

The channels come from a collection of parameters.

Channel Primitives

The channels come from a collection of channel primitives on the skeleton topology geometry of each MotionClip.

Source Node

The node with the parameters for defining the key poses of the MotionClips. When turned off, the immediate input(s) to this SOP are used.

This parameter is available when Key Source is set to Parameters.

Source Parameters

The parameters on the Source Node that are used to define the key poses of the MotionClips.

This parameter is available when Key Source is set to Parameters.

Channel Primitives

The group of channel primitives on the skeleton topology geometry of each MotionClip that define their key poses.

This parameter is available when Key Source is set to Channel Primitives.

Inputs

First Input

The skeleton animation to be cached.

Nth Input

If Pack Inputs is turned on, each input’s clip is stored in its own packed primitive.

Outputs

MotionClip

The cached skeleton animation.

Examples

SimpleMotionClip Example for MotionClip geometry node

This examples demonstrates how to create a motion clip from a skeleton animation.

See also

Geometry nodes