Struct SoftBodyMaterial 

pub struct SoftBodyMaterial {

    pub edge_softness: SpringCoefficients<f32>,
    pub bend_softness: SpringCoefficients<f32>,
    pub volume_softness: SpringCoefficients<f32>,
    pub shape_matching_softness: SpringCoefficients<f32>,
    pub young_modulus: f32,
    pub poisson_ratio: f32,
    pub elastic_damping_ratio: f32,
    pub plastic_yield: f32,
    pub plastic_creep: f32,
    pub plastic_max: f32,
    pub deformation_damping: f32,
    pub edge_plastic_yield: f32,
    pub edge_plastic_creep: f32,
    pub edge_plastic_max: f32,
    pub edge_plastic_flow: SoftEdgePlasticFlow,
    pub tear_strain: Option<f32>,
    pub tear_force: Option<f32>,
    pub tear_smoothing: f32,
    pub interior_strength: f32,
    pub max_tears_per_step: u32,
    pub min_piece: Option<u32>,
}

The stiffness and damping of every soft-body constraint family: a natural_frequency (Hz) and damping_ratio per family, normalized by the constraint’s effective mass (independent of mass, substeps and timestep); a frequency far above the substep rate saturates instead of exploding.

Fields

edge_softness: SpringCoefficients<f32>

Softness of the structural edges.

bend_softness: SpringCoefficients<f32>

Softness of the bending edges and dihedral constraints.

volume_softness: SpringCoefficients<f32>

Softness of the per-cell volume constraints (crate::dynamics::SoftBodyCellModel::Volume) and of the global volume-preservation constraint.

shape_matching_softness: SpringCoefficients<f32>

Softness of the shape-matching constraints.

young_modulus: f32

Young’s modulus of the elastic cells (crate::dynamics::SoftBodyCellModel::Corotational and crate::dynamics::SoftBodyCellModel::NeoHookean), in force per unit area (3D) or length (2D); their natural frequency derives from it, so a finer mesh does not get stiffer.

poisson_ratio: f32

Poisson’s ratio of the elastic cells, in [0, 0.5).

elastic_damping_ratio: f32

Damping ratio of the elastic cells.

plastic_yield: f32

Plastic yield of the elastic cells: the strain (Frobenius norm of the deviatoric part of sym(RᵀF) - I, read from stress by the constraint solver) beyond which a cell’s rest shape flows toward its current shape (default: 0.0, no plasticity).

plastic_creep: f32

Rate (per second) at which the strain in excess of the yield is absorbed into the rest shape (default: 1.0); the flow is deviatoric (volume preserving).

plastic_max: f32

Largest accumulated plastic deformation of a cell, the Frobenius norm of P - I with P its rest shape’s plastic stretch (default: 1.0). Flow past it is projected back onto the bound, so a crushed cell cannot flow toward a sliver; an inverted cell never flows.

deformation_damping: f32

Rate (per second) at which the particles’ velocities are pulled toward the body’s best-fit rigid motion, damping every deformation mode but not the whole-body motion; a few units per second settle a stiff slender body’s residual bending sway (default: 0.0, off).

edge_plastic_yield: f32

Plastic yield of the edges (structural and bending): the strain |length / rest_length - 1| beyond which the rest length flows toward the current length (default: 0.0, none), at the rate Self::edge_plastic_creep, up to edge_plastic_max; tears use the initial length.

edge_plastic_creep: f32

Rate (per second) at which an edge’s strain in excess of its yield is absorbed into its rest length (default: 1.0); Real::INFINITY (or anything above the step rate) sets it at once.

edge_plastic_max: f32

Largest permanent set an edge may accumulate, as a fraction of its initial length (default: 0.5); past it the edge stops yielding and stays elastic, so a crushed edge cannot flow to nothing.

edge_plastic_flow: SoftEdgePlasticFlow

Whether the edges take a permanent set under a squeeze, a stretch, or both (default: both).

tear_strain: Option<f32>

Strain beyond which elements break (default: None, unbreakable): an edge stretched past this fraction of its initial rest length, or a corotational cell whose largest tensile principal strain (capped at 1.0) exceeds it, tears at step end; volume cells never do.

tear_force: Option<f32>

Force beyond which the edges break (default: None): an edge whose force along its direction (its impulse over the substep, positive when resisting stretching) exceeds it is torn at the end of the step. Either criterion tears an edge; cells tear on strain only.

tear_smoothing: f32

Time constant, in seconds, over which an element’s load is smoothed exponentially before the tear test (default: 0.0, one step past the threshold tears); applies to the strain and force criteria alike, and crate::dynamics::SoftBodyEdge::stress reads the smoothed load.

interior_strength: f32

How much tougher an undamaged interior element (no particle on the surface or on an earlier tear) is than a surface one (default: 1.0): it needs this many times its tear threshold, so tears start at the surface or existing damage and run inward; scales tear_resistance.

max_tears_per_step: u32

Maximum number of edges torn per step (default: u32::MAX, no limit): the most loaded go first, the others wait for the next step (edges past twice their threshold always tear). Bounding it paces the cracks of a taut sheet but lets a projectile be caught as in a net.

min_piece: Option<u32>

The smallest piece, in measure elements, a tear may split off (default: None: ten triangles for a 3D cloth, three cells in 2D or six in 3D, three segments for a rope). A tear leaving a smaller piece waits (cuts are exempt); Some(1) lets a tear shed single elements.

Implementations

impl SoftBodyMaterial

pub fn uniform(softness: SpringCoefficients<f32>) -> Self

A material with the same softness for every spring family (edges, bending, volume, shape matching); the elastic-cell parameters keep their defaults.

pub fn tears(&self) -> bool

Whether some tear criterion is set (tear_strain or tear_force).

pub fn lame_parameters(&self) -> (f32, f32)

The Lamé parameters (μ, λ) of the elastic cells.

Trait Implementations

impl Clone for SoftBodyMaterial

fn clone(&self) -> SoftBodyMaterial

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for SoftBodyMaterial

impl Debug for SoftBodyMaterial

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for SoftBodyMaterial

fn default() -> Self

Returns the “default value” for a type.

impl PartialEq for SoftBodyMaterial

fn eq(&self, other: &SoftBodyMaterial) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for SoftBodyMaterial