Struct FoldLine 

pub struct FoldLine {
    pub start: Vec3,
    pub end: Vec3,
    pub direction: Vec3,
    pub fold_angle: f64,
    pub fold_type: FoldType,
    pub adjacent_facets: [Option<usize>; 2],
}

A single crease line in an origami pattern.

Stores the geometric position and direction of the fold, the current dihedral (fold) angle, and whether it is a mountain or valley crease.

Fields

start: Vec3

Start point of the fold line (in reference flat configuration).

end: Vec3

End point of the fold line (in reference flat configuration).

direction: Vec3

Unit direction from start to end.

fold_angle: f64

Dihedral fold angle in radians. 0 = flat, π = fully folded.

fold_type: FoldType

Mountain or valley type.

adjacent_facets: [Option<usize>; 2]

Indices of the two facets on either side of this crease (if any).

Implementations

impl FoldLine

pub fn new(start: Vec3, end: Vec3, fold_type: FoldType) -> Self

Create a new fold line from two end points.

pub fn length(&self) -> f64

Length of the crease segment.

pub fn midpoint(&self) -> Vec3

Mid-point of the crease.

pub fn signed_angle(&self) -> f64

Signed fold angle: positive for mountain, negative for valley.

pub fn rotation_matrix(&self) -> [[f64; 3]; 3]

Rotation matrix that rotates about the fold axis by fold_angle.

Uses Rodrigues’ rotation formula.

pub fn apply_rotation(&self, point: &Vec3) -> Vec3

Apply the fold rotation to a point relative to the fold line start.

Trait Implementations

impl Clone for FoldLine

fn clone(&self) -> FoldLine

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for FoldLine

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

Formats the value using the given formatter.