Houdini 20.5 Nodes Geometry nodes

Ragdoll Collision Shapes 2.0 geometry node

Creates collision shapes for a KineFX skeleton to be used in a ragdoll RBD simulation.

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Since 20.0

This node provides an interactive way of creating and modifying collision shapes for a KineFX skeleton for the purpose of running it through a ragdoll RBD simulation.

Parameters

Group

The joints to build collision shapes for. Joints outside of this group are not configurable.

Rest Pose Attribute

The specified rest transform point attribute is used to set the skeleton to its rest state before creating the collision shapes.

Group Name

When turned on, outputs the specified point group on the skeleton which holds all the joints that have a corresponding collision shape.

Clear Overrides

Clears all manual overrides added from the node’s viewer state.

Generate Shapes

Generate Shapes Group

The joints to build collision shapes for, using the Generate Convex Hulls from Skin Geometry and Generate Basic Shapes options. If Generate Convex Hulls from Skin Geometry or Generate Basic Shapes is turned off, joints that are not included in the Generate Shapes Group are unconfigurable.

If Generate Convex Hulls from Skin Geometry is turned on, joints that are not included in the Generate Shapes Group will have their corresponding collision shapes merged together with the shape of the first found parent joint. This is useful in scenarios when, for example, you want to treat the hand of a humanoid character as a single shape and not have a separate shape for each finger segment.

Generate Convex Hulls from Skin Geometry

When turned on, generates collision shapes for all the joints in the input skeleton that have an influence on the deformation of the Rest Geometry input, i.e. joints that have been skinned to the Rest Geometry. The resulting shapes are built using the selected algorithm that creates convex hulls. The available algorithms from the drop-down menu are Shrinkwrap and Convex Decomposition. See the Shrinkwrap and Convex Decomposition SOPs for more information.

This option requires a Rest Geometry input with a valid boneCapture point attribute.

Note

The resulting collision shapes are built from the Rest Geometry input and are not transformed based on the Rest Pose Attribute of the skeleton. The skeleton is only used here to slice up the skin by capture regions. This means that if the provided Rest Pose Attribute is different from the Capture Pose of the skeleton, the Rest Pose Attribute pose and the resulting collision shapes will not match, which will cause issues downstream.

If the Rest Pose Attribute pose is different from the skeleton’s Capture Pose, you can:

  • Use a Joint Deform SOP upstream from this SOP to deform the Rest Geometry input so that it matches the Rest Pose Attribute of the skeleton.

    or

  • Deform the resulting collision shapes downstream from this SOP so that the shapes match the Rest Pose Attribute of the skeleton.

Max Concavity

This parameter is available when Generate Convex Hulls from Skin Geometry is turned on, and the algorithm selected from the drop-down menu is Convex Decomposition. See the Convex Decomposition SOP for more information.

Generate Basic Shapes

When turned on, generates basic collision shapes for all the joints in the input skeleton. This method attempts to position and scale the newly created basic shapes using the skeleton’s hierarchy. Select the basic shape to use from the drop-down menu.

Guide Geometry

Display Guides at Rest Transform

When turned on, displays the guide geometry at the rest transform.

Tip

Turning this off allows you to visualize the shape intersections that may appear throughout the input animation.

Display Collision Shapes

When turned on, displays the guide geometry for the collision shapes in the viewport.

Display Intersections

When turned on, guide geometry showing intersections between collision shapes is displayed in bright red. These intersections usually cause instability when trying to run the solver.

Inputs

Skeleton

The input skeleton to be processed.

Collision Shapes

Custom shapes to assign as collision shapes. These shapes are expected to be in a packed geometry format and have a valid name primitive attribute.

Rest Geometry

The character’s skin, at rest pose, that is used to procedurally generate collision shapes using the capture data.

See Generate Convex Hulls from Skin Geometry for more details.

Outputs

Skeleton

The input skeleton unmodified.

If Group Name is turned on, a point group is created on the skeleton.

Collision Shapes

The collision shape geometry.

See also

Geometry nodes