Struct MassProperties 

pub struct MassProperties {
    pub mass: f64,
    pub centre: Point,
    pub inertia: Matrix3,
    pub deflection: f64,
}

How much of something there is, and how it is distributed.

Fields

mass: f64

The measure: length, area or volume, depending on what was asked for.

Never negative. A volume computed from an inward-wound shell would come out negative, which says the shell is inside out rather than that the solid has negative volume, so that case is an error instead.

centre: Point

The centre of the measure: the centroid, or centre of mass at uniform density.

inertia: Matrix3

The inertia tensor about MassProperties::centre, at unit density.

About the centre, not the origin: an inertia about the origin says as much about where the part happens to sit as about the part. MassProperties::inertia_about moves it elsewhere.

deflection: f64

The chord deflection the tessellation was built to.

The honest statement of accuracy. For a shape with only planar faces and straight edges the result is exact whatever this says, because the tessellation is exact.

Implementations

impl MassProperties

pub const fn none(deflection: f64) -> Self

Nothing: no mass, at the origin, resisting nothing.

pub fn inertia_about(&self, point: Point) -> Matrix3

The inertia tensor about some other point, by the parallel axis theorem.

pub fn radius_of_gyration(&self, axis: Direction) -> Option<f64>

The radius of gyration about an axis through the centre.

The distance at which a point of the same mass would have the same inertia. Zero mass has no such distance, so this returns None rather than dividing by it.

pub fn principal_axes( &self, tol: Tolerances, ) -> OgeomResult<[(f64, Direction); 3]>

The principal moments, smallest first, with the axes they act about.

The eigenvectors of a symmetric tensor, so the axes are orthogonal. A shape with rotational symmetry has repeated moments and the axes in that plane are arbitrary but still orthogonal, which is correct, not a failure: any pair of perpendicular axes in that plane is principal.

Errors

OgeomError::NotDone if the eigen-solver does not converge, which for a symmetric 3×3 means the tensor was not finite.

Trait Implementations

impl Clone for MassProperties

fn clone(&self) -> MassProperties

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for MassProperties

impl Debug for MassProperties

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

Formats the value using the given formatter.

impl PartialEq for MassProperties

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for MassProperties