API

SignedDistanceField(grid, ϕ)

A signed distance field (SDF) defined on a Cartesian grid.

This type is the return value of sdf. The scalar field values are stored in ϕ with the same shape as grid.

Fields

• grid: Sampling grid (provides axes and spacing).
• ϕ: Signed distance values on the grid nodes.

Interpolation (external)

This package does not bundle interpolation. You can interpolate ϕ using Interpolations.jl (or similar) by passing the grid axes and the field values.

Examples

julia> using Interpolations

julia> itp = linear_interpolation(sdf.grid.axes, sdf.ϕ);

sdf(path::String; spacing=:auto, minres=128, padding=1, datatype=Float64, progress=false)

Generate a 3D signed distance field (SDF) from a triangle mesh file.

Arguments

• path: Path to a mesh file supported by MeshIO.jl.

Keyword arguments

• spacing: Grid spacing. Use a number or :auto (chosen from the mesh bounding box using minres).
• minres: Minimum resolution along the longest bounding-box axis when spacing=:auto.
• padding: Extra margin around the mesh in multiples of the grid spacing.
• datatype: Floating-point type used for computation (default: Float64).
• progress: Show progress meter.

sdf(points; spacing=:auto, minres=128, padding=1, datatype=Float64, progress=false)

Generate a 2D signed distance field (SDF) from a closed polyline.

The polyline is closed implicitly by connecting the last point back to the first.

Arguments

• points: Either
  • a 2×N matrix (each column is a vertex), or
  • a vector of 2D vertices (StaticVector{2}).

Keyword arguments

• spacing: Grid spacing. Use a number or :auto (chosen from minres).
• minres: Minimum resolution along the longest bounding-box axis when spacing=:auto.
• padding: Extra margin around the polyline in multiples of the grid spacing.
• datatype: Floating-point type used for computation (default: Float64).
• progress: Show progress meter.

Examples

julia> sdf = GeometrySDF.sdf([0.0 1.0; 0.2886751346 0.5; 0.8660254038 0.5; 0.5773502692 0.0; 0.8660254038 -0.5; 0.2886751346 -0.5; 0.0 -1.0; -0.2886751346 -0.5; -0.8660254038 -0.5; -0.5773502692 0.0; -0.8660254038 0.5; -0.2886751346 0.5]');

julia> GeometrySDF.writevtk("hexagram", sdf)
1-element Vector{String}:
 "hexagram.vti"

writevtk(path::String, sdf::SignedDistanceField)

Write a SignedDistanceField to a VTK structured grid file.

The output stores the grid coordinates (sdf.grid.axes) and the signed distance values (sdf.ϕ) as a scalar field named "Signed distance" for visualization in ParaView.

Arguments

• path: Output file path (without extension is fine; WriteVTK.jl will append as needed).
• sdf: Signed distance field generated by sdf.