Houdini 20.5 Nodes Geometry nodes

Skeleton geometry node

Interactively creates and edits geometry-based skeletons.

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Since 18.5

This node allows you to non-procedurally create a geometry-based skeleton and edit its properties.

State

Skeleton state hotkeys

Hotkey or Interaction

Action

F

Toggles between Create and Modify mode.

G

Toggles Tweak Mode.

H

Toggles the display of the transform handle.

Click in empty space while in Create mode

Creates a new joint.

⇧ Shift click in empty space while in Create mode

Creates a floating, unparented joint.

click or click a joint while in Modify mode

Selects a joint.

click or click a joint while in Create mode

Creates a new joint with the clicked joint as its parent.

Double-click a joint

Selects the clicked joint and all the joints in its joint chain.

Hold S and drag

Box select joints.

⇧ Shift click a joint

Adds the joint to the selection group.

⌃ Ctrl click a joint

Removes the joint from the selection group.

⇧ Shift + ⌃ Ctrl click a joint’s link or poly line (geometry)

Adds a new joint between the existing joints, effectively splitting the poly line in half.

Delete

Removes the selected joint and reparents its descendants to the joint’s former parent.

⇧ Shift + Delete

Removes the selected joint and does not reparent its descendants.

Drag a joint while in Tweak mode

Moves the joint and its descendants.

⇧ Shift drag a joint while in Tweak mode

Moves the joint without moving its descendants.

Drag a joint while in Tweak mode with Child Compensate turned on

Moves the joint without moving its descendants.

⇧ Shift drag a joint while in Tweak mode with Child Compensate turned on

Moves the joint and its descendants.

⇧ Shift drag a poly line while in Tweak mode

Twists or rotates the poly line and its parent/child pair of joints.

⌃ Ctrl drag a poly line while in Tweak mode

Rotates the poly line using its parent joint as a pivot. This is also called trackball rotation.

⌃ Ctrl + ⇧ Shift drag a poly line while in Tweak mode

Rotates the poly line along the existing curvature.

⎋ Esc

Exits the Skeleton state.

Skeleton state toolbar

Name

The name of the selected joint.

Mode

Choose between creating and modifying a skeleton.

Scale Inheritance

Determines how the transforms of the selected joint are affected by the scaling of its parent. To see a joint’s transform values, select the joint and press P over the viewport to bring up the Parameters window. See scale inheritance for descriptions of the available options.

Joint Placement

When drawing a skeleton, this specifies how the joints are placed on the geometry. See joint placement options for more information.

View Based

Places joints at the mid-point of the geometry.

Normal Based

Places joints at the mid-point of the geometry, using the normal of the surface.

Freehand

If the construction plane is displayed, the joints are snapped onto the construction plane. If the construction plane is not displayed, the joints are placed on a plane perpendicular to your viewing angle.

Surface

Places joints on the surface of the geometry.

Tweak Mode, Child Compensate

When Tweak Mode is on, and Child Compensate is off, dragging a joint moves the joint and its descendants.

When Tweak Mode and Child Compensate are both on, dragging a joint only moves the joint and not its descendants.

Skeleton state visualizers

Visual Feedback

Meaning

White joint

Unselected joint.

Yellow joint

Selected joint.

Red joints

Indicates a cyclical (invalid) hierarchy.

Parameters

Stash Input

Removes all existing changes and makes a copy of the input geometry as the node’s starting point. This allows you to start from an existing skeleton.

Stash Merge Input

Appends a copy of the input geometry. This allows you to add an existing skeleton without losing your current changes.

Update Stash From Output

Incorporates changes at the current frame for editing. This is useful for updating the skeleton when Transfer Input Animation is turned on.

Transfer Input Animation

When turned on, copies the transforms from the matching input joints and updates all the other joints appropriately.

Cache Output

When Transfer Input Animation is turned on, this enables caching of the evaluation results for faster playback.

Joint Color

The color to assign to the joints.

Inputs

Skeleton

The template geometry to build from. This is used by the Stash Input and Stash Merge Input parameters.

Outputs

Skeleton

The authored SOP skeleton.

See also

Geometry nodes