Skeleton Asset

The main function of the Skeleton asset is to store information about the bone hierarchy in an animated mesh. Here you adjust the overall scale and rotation of imported animated meshes. The skeleton asset is also where you define physics collision shapes and joint limits for the bones, which are used by ragdolls and hitboxes.

Asset Properties

• File: The file from which to import the skeleton information. This is typically the same file as in the animated mesh asset.

• ImportTransform: A preset for the orientation of the imported file. Blender_YUp and Blender_ZUp match the two common export conventions from Blender; choose Custom to set the directions yourself with the properties below.

• RightDir, UpDir, FlipForwardDir: These properties are the same as on the mesh asset. Depending on how the mesh was exported, you may need to adjust these to have the skeleton (and every mesh that uses this skeleton) stand upright and look into the correct direction.

  In Blender it is common to model meshes such that they face the user when the front view is active (Numpad 1):

  

  With such an orientation the right side of the model points into the -X direction. The +Z axis corresponds to the up direction and the model looks into the +Y direction. When you export such a model to GLTF/GLB, you can keep this convention (Y up disabled in the export settings) or you can export it in the more common convention of using +Y as the up axis (Y up enabled). Both conventions can be mapped to PLASMA's preferred convention like so:

  For GLB files exported from Blender with Y up use:

  • RightDir = Negative X
  • UpDir = Positive Y
  • FlipForward = off

  For GLB files exported from Blender with Z up use:

  • RightDir = Negative X
  • UpDir = Positive Z
  • FlipForward = off

  Note that in Plasma the convention is that models look along the +X axis. Every component (such as AI) assumes that moving along the +X axis will move the mesh forward, moving along +Y moves it to the right and moving along +Z moves it upwards. It is therefore best to import all meshes this way right away.

• UniformScaling: The overall size of the skeleton. Use this if you need to adjust from centimeters to meters.

• BoneDirection: This setting only affects the visualization of the skeleton. It has no effect on the actual mesh skinning. It is used to tell the visualizer which cardinal direction the bones should point into. You only need to change this setting, if the skeleton visualization looks all wrong (all lines point into weird directions). You need to transform the asset to apply the change. Just try all options until it looks right.

• PreviewMesh: The animated mesh to show in the asset's 3D view, so that you can see the collision shapes and joint limits against the actual model.

• CollisionLayer, Surface: The default collision layer and surface for all bone collision shapes. Individual joints can override both.

• MaxImpulse: The maximum impulse a ragdoll built from this skeleton may receive from a single hit, to keep it from flying off unrealistically.

• LeftFootJoint, RightFootJoint: The names of the foot bones. These are used by animation features that need to know where the feet are, such as foot IK.

• HumanoidRigType, HumanoidJointNames: Set the rig type to Humanoid and map the standard humanoid bone slots (hips, spine, head, limbs) to the bone names of this skeleton. This lets animation clips authored for one humanoid skeleton be retargeted to another.

Humanoid Mapping

The Humanoid tab provides the rig type, bone mapping, auto-mapping, and reference-pose controls. Check the mapping against the imported hierarchy before using it for retargeting.

Joint Properties

Select a joint in the skeleton tree to edit it. Besides its name and local rotation, each joint has:

• JointType, Stiffness, SwingLimitY, SwingLimitZ, TwistLimitHalfAngle, TwistLimitCenterAngle: The physics joint that connects this bone to its parent in a ragdoll, and how far it may swing and twist. Enable VisualizeSwingLimits and VisualizeTwistLimits on the skeleton component to see the cones in the 3D view.

• OverrideSurface, OverrideCollisionLayer: Use a different surface or collision layer for this bone than the skeleton default.

• BoneShapes: Box, capsule, or sphere collision shapes attached to the bone. A shape with a length of 0 automatically spans from the parent joint to this joint.

• Colliders: Convex mesh colliders for bones that need a more accurate shape than a primitive.

See Also

• Skeletal Animations
• Animated Mesh Asset
• Skeleton Component