Boobs Physics

Adds physics simulation to breast bones on the model. Selected bones are given suspension joints that allow them to bounce and sway with movement, plus optional collision shapes that interact with arms and the ground.

Bone Selection

Use Select Bones to pick which bones receive physics. Opens a bone picker dialog starting from the torso — select one or two bones (left and right). Presets let you save and restore configurations across different models.

Suspension

Adds spring-damper joints that anchor each bone to its parent. Controls bounce, sway, and rotation limits. See the Suspension sub-panel for detailed joint settings.

Collision

Enables SDF collider shapes (cone-like capsules) around each breast bone so they interact with arms, clothing, and the ground. Collider Radius and Collider Length set the overall size. Collider Curve shapes the profile — negative values make it more bulbous, positive values taper it toward the tip. Enable Nipple adds a small spherical collider with adjustable Nipple Position and Nipple Size. Friction controls how surfaces slide against the collider. Collide With Arms assigns the collider to a separate layer for arm-specific interactions. Visualize renders the 3D collider meshes for debugging.

Both Collider Curve and Enable Nipple are designed to work with cloth simulation, giving clothing something to slide against.

Softbody

Overlays a particle-based XPBD softbody on the child bones of each selected root, adding jiggle deformation on top of the rigid suspension physics. See the Softbody sub-panel for particle settings.

Sub-Components

Suspension

Adds a spring-damper suspension joint to a bone, anchoring it to its parent with configurable Anchor position and Center Offset. Spring Force, Damping, Mass, and Drag control the joint dynamics. Radius sets the collider size; Rest Angle adds a rotational bias. Rotation Limit constrains swing and twist angles with their own spring and damping. Visualize Joints renders the constraint shape.

Softbody

Defines a particle-based XPBD softbody mesh that deforms with physics. Child bones of each selected root become simulation particles arranged in layers extending outward. Depth controls how far particles extend from the bone; Edge Depth pulls edge particles closer to the skeleton for a tighter fit. Layers and Subdivision increase mesh resolution at the cost of performance. Depth Distribution shifts volume between inner and outer layers.

The constraint sliders (Volume, Edge, Rotation) control particle stiffness — higher values mean less deformation. Constraint Damping smooths oscillation between solver steps. Inertia adds resistance to rapid movement changes. Show Bones renders the original skeleton bones alongside the particle mesh for comparison.