minkowski

Modules

Module	Description
modeling/minkowski	Minkowski sum operations for 3D geometries.

Functions

Name	Description
minkowskiSumNonConvexConvex()	Compute Minkowski sum of non-convex A with convex B.
decomposeIntoTetrahedra()	Decompose a geom3 into tetrahedra using face-local apex points. Each resulting tetrahedron is guaranteed to be convex.
createTetrahedronPolygons()	Create the 4 triangular faces of a tetrahedron.
minkowskiSumConvex()	Compute Minkowski sum of two convex polyhedra.
extractUniqueVertices()	Extract unique vertices from a geom3. Uses a Set with string keys for deduplication.

modeling/minkowski

Minkowski sum operations for 3D geometries.

The Minkowski sum of two shapes A and B is the set of all points that are the sum of a point in A and a point in B. This is useful for:

• Offsetting/inflating shapes (using a sphere creates rounded edges)
• Collision detection (shapes collide iff their Minkowski difference contains origin)
• Motion planning and swept volumes

Example

const { minkowskiSum } = require('@jscad/modeling').minkowski
const rounded = minkowskiSum(cube, sphere)

modeling/minkowski.minkowskiSum(...geometries)

Compute the Minkowski sum of two 3D geometries.

The Minkowski sum A ⊕ B is the set of all points a + b where a ∈ A and b ∈ B. Geometrically, this "inflates" geometry A by the shape of geometry B.

Common use cases:

• Offset a solid by a sphere to round all edges and corners
• Offset a solid by a cube to create chamfered edges
• Collision detection (if Minkowski sum contains origin, shapes overlap)

For best performance, use convex geometries. Non-convex geometries are supported when the second operand is convex, but require decomposition and are slower.

Kind: static method of modeling/minkowski
Returns: geom3 - new 3D geometry representing the Minkowski sum

Param	Type	Description
...geometries	Object	two geom3 geometries (second should be convex for non-convex first)

Example

const { primitives, minkowski } = require('@jscad/modeling')
const cube = primitives.cuboid({ size: [10, 10, 10] })
const sphere = primitives.sphere({ radius: 2, segments: 16 })
const rounded = minkowski.minkowskiSum(cube, sphere)

minkowskiSumNonConvexConvex()

Compute Minkowski sum of non-convex A with convex B.

Decomposes A into tetrahedra, computes Minkowski sum of each with B, then unions all results.

Kind: global function

decomposeIntoTetrahedra()

Decompose a geom3 into tetrahedra using face-local apex points. Each resulting tetrahedron is guaranteed to be convex.

Unlike centroid-based decomposition, this approach works correctly for shapes where the centroid is outside the geometry (e.g., torus, U-shapes). Each polygon gets its own apex point, offset inward along its normal.

Kind: global function

createTetrahedronPolygons()

Create the 4 triangular faces of a tetrahedron.

Kind: global function

minkowskiSumConvex()

Compute Minkowski sum of two convex polyhedra.

For convex polyhedra, the Minkowski sum equals the convex hull of all pairwise vertex sums. This is O(n*m) for n and m vertices, plus the cost of the convex hull algorithm.

Kind: global function

extractUniqueVertices()

Extract unique vertices from a geom3. Uses a Set with string keys for deduplication.

Kind: global function