RadiativeViewFactor.jl

A Julia package for computing radiative view factors between arbitrary surfaces (3-D) or curves (2-D) on structured or unstructured meshes of first- or second-order triangles, quadrilaterals, and lines, mixable within one mesh. Any format readable with Gmsh is supported, plus XML VTK (.vtu) via an optional ReadVTK.jl extension, and Nek5000/NekRS .re2 files. Integration is by Gauss-Legendre quadrature, Monte Carlo pair-area sampling, Sauter-Schwab-type Duffy transformation of singular element pairs, or ray-shooting Monte Carlo, all with BVH-accelerated obstruction. Runs multi-threaded on the CPU and on NVIDIA CUDA and Apple Metal GPUs via KernelAbstractions.jl.

Quick Start

3D surface mesh — deterministic quadrature

using RadiativeViewFactor

mesh   = load_mesh("geometry.msh")   # surface_dim=2 is the default
result = compute_view_factors(mesh; nquad=4)

# F_group[i,j] = view factor from group_names[i] to group_names[j]
println(result.group_names)
println(result.F_group)

# Look up a specific pair by name
i = findfirst(==("emitter"),  result.group_names)
j = findfirst(==("receiver"), result.group_names)
println("F(emitter → receiver) = ", result.F_group[i, j])

check_reciprocity(result)   # prints max relative error of Aᵢ Fᵢⱼ = Aⱼ Fⱼᵢ
check_closure(result)       # prints row-sum range

With Duffy transformation (near corner/edge singularities)

# Automatically detects shared vertices and edges between Quad8 elements
# and applies the Sauter–Schwab regularization only where needed.
result = compute_view_factors(mesh; nquad=6, use_duffy=true)

Monte Carlo

result = compute_view_factors(mesh; monte_carlo=true, n_samples=50000)

# Reproducible result with a fixed seed
using Random
result = compute_view_factors(mesh; monte_carlo=true, n_samples=50000,
                               rng=MersenneTwister(42))

Ray-shooting Monte Carlo (fastest for large or obstructed 3D meshes)

# compute on CPU kernel
result = compute_view_factors(mesh; raytrace=true, n_rays=10000)               

# compute using your choice of random seed
using Random
result = compute_view_factors(mesh; raytrace=true, n_rays=10000, rng=Xoshiro(42))

# compute on Nvidia or Apple GPU architecture
using CUDA   # or Metal
result = compute_view_factors(mesh; raytrace=true, n_rays=10000,
                            backend=CUDABackend() #= backend=MetalBackend() =#)