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Triangle Barycentric Point

Map three supplied barycentric weights summing to one to a planar triangle point; weights may be negative, no inside-triangle claim.

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Description

Map three supplied barycentric weights summing to one to a planar triangle point; weights may be negative, no inside-triangle claim.

Planar geometry operates on two-coordinate Cartesian points and explicit shape boundaries. A closed rectangle includes its edges, while a segment parameter locates a point along a supporting line. Signed cross products, areas and axis gaps preserve orientation or direction information that a magnitude alone would lose.

Map three supplied barycentric weights summing to one to a planar triangle point; weights may be negative, no inside-triangle claim.

When to use this tool

Use this tool to map three supplied barycentric weights summing to one to a planar triangle point; weights may be negative, no inside-triangle claim.

How to use the tool and how it works

  1. Enter vertices, weights using the input definitions below.
  2. Run the operation. Resolve malformed-input errors before interpreting the result.
  3. Read result.point. Interpret signs, units, ordering and null values using the rules below.

Require exactly three planar vertices and weights with |sum−1| < 10⁻¹². Return the coordinatewise weighted sum of the three vertices in their supplied order.1

Input fieldMeaning and unitsAccepted input
verticesExactly three planar vertices [[Ax,Ay],[Bx,By],[Cx,Cy]] in weight order.Dense list of at most 128 rows of at most 128 finite numbers; the operation’s shape constraints also apply.
weightsThree dimensionless barycentric weights in the supplied vertex order.Dense list of at most 128 finite numbers, subject to the stated integer/shape rules.
Output fieldInterpretation
resultObject containing the fields below.
result.pointResulting planar [x,y] point in coordinate units.
json
{
  "input": {
    "vertices": [
      [
        0,
        0
      ],
      [
        2,
        0
      ],
      [
        0,
        2
      ]
    ],
    "weights": [
      0.5,
      0.25,
      0.25
    ]
  },
  "output": {
    "result": {
      "point": [
        0.5,
        0.5
      ]
    }
  }
}

Limitations and assumptions

  • Weights may be negative, and triangle degeneracy is not rejected by this forward weighted sum.
  • Point components and rectangle bounds are finite within ±1,000,000,000. Rectangles use [minX,minY,maxX,maxY] with ordered inclusive bounds. Floating arithmetic is used without an implicit robustness tolerance.
  • Every declared top-level input is required and unknown fields are rejected. Ordinary strings are limited to 8,192 UTF-16 code units and lists to 128 entries, with tighter operation-specific bounds where stated. JSON text has bounded nesting and node counts.
  • Numeric outputs must be finite and within the absolute safe-integer magnitude; exact larger integers use decimal text. Source positions are zero-based UTF-16 offsets and span ends are exclusive unless a different convention is explicitly stated.

Alternative or Complementary methods

Choose the boundary and coordinate convention explicitly. Use robust geometric predicates or a topology-aware library when near-coincidence, holes, invalid polygons or geographic coordinates matter.

References

  1. Tool behavior and example: Triangle Barycentric Point — tool.io

Similar or alternative tools

  • Triangle Point Barycentric Coordinates

    Invert planar barycentric coordinates on a nondegenerate supplied triangle; floating arithmetic and signed exterior weights are retained.

  • Triangle Barycentric Membership

    Audit supplied three-coordinate barycentric closed-triangle membership with an explicit nonnegative absolute tolerance; does not validate a triangle’s geometry.