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RadiativeViewFactor.jl

A Julia package for computing radiative view factors between arbitrary surfaces or curves. Meshes may be structured or unstructured and 1st- or 2nd-order; any Gmsh-readable format is supported, plus XML VTK (.vtu) via an optional ReadVTK.jl extension and Nek5000/NekRS .re2 meshes through a built-in reader.

Overview

RadiativeViewFactor.jl evaluates the double-surface integral that defines the geometric view factor between pairs of finite surfaces. The geometry is supplied as a mesh: the solver works from element node connectivity alone, so structured and unstructured meshes are treated identically, and 1st- and 2nd-order elements may be mixed freely. Four integration strategies are available:

  • Gauss–Legendre quadrature — the default; spectral convergence for smooth geometries
  • Monte Carlo (pair-area sampling) — stratified sampling of point pairs on each element pair; adjacent and near pairs are patched with the Duffy transformation automatically
  • Duffy transformation — singularity-regularizing change of variables for Quad4/Quad8 element pairs sharing a vertex or edge; gives accurate results for inclined surfaces with common edges
  • Monte Carlo (ray-shooting) — cosine-weighted rays shot from each element into the whole scene at once; the fastest method for large or obstructed 3D meshes, since obstruction and visibility fall out of the same BVH query

All four methods run on CPU and support obstruction detection via BVH-accelerated ray casting. Quadrature, both Monte Carlo variants, and obstruction also run on GPU (CUDA and Metal), and so does the Duffy transformation, for 3-D surface meshes.

Beyond the integrators, the package can:

  • restrict the radiating surface to a subset of groups while every group still shadows (radiating_groups), which cuts the cost from O(N_total²) to O(N_radiating²)
  • skip element pairs that provably cannot see each other (facing_cull, on by default)
  • check reciprocity and closure of a result, and enforce both on a closed enclosure (enforce_closure)
  • write view factors for a Nek5000/NekRS surface-to-surface radiation case (write_nekrs_view_factors)

Installation

using Pkg
Pkg.add("RadiativeViewFactor")

RadiativeViewFactor.jl is registered in the Julia General registry.

Requires Julia 1.10 or later.

For GPU support, install the relevant backend before loading the package:

Pkg.add("CUDA")   # NVIDIA
Pkg.add("Metal")  # Apple Silicon

For mesh visualisation:

Pkg.add("Plots")   # enables plot_mesh_normals

For loading XML VTK (.vtu) meshes:

Pkg.add("ReadVTK")

Quick Example

using RadiativeViewFactor

mesh   = load_mesh("geometry.msh")
result = compute_view_factors(mesh; nquad=4)

i = findfirst(==("emitter"),  result.group_names)
j = findfirst(==("receiver"), result.group_names)
println("F(emitter → receiver) = ", result.F_group[i, j])

check_reciprocity(result)
check_closure(result)

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