voxcity.simulator_gpu.solar.svf.SVFCalculator¶

class voxcity.simulator_gpu.solar.svf.SVFCalculator(domain, n_azimuth: int = 80, n_elevation: int = 40)¶

GPU-accelerated Sky View Factor calculator.

Computes SVF by tracing rays from each surface to the hemisphere. SVF = fraction of hemisphere visible from surface.

domain¶

nx¶

ny¶

nz¶

dx¶

dy¶

dz¶

n_azimuth = 80¶

n_elevation = 40¶

n_directions = 3200¶

max_dist¶

directions¶

solid_angles¶

total_solid_angle¶

compute_svf(surf_pos: ti.template(), surf_dir: ti.template(), is_solid: ti.template(), n_surf: taichi.i32, svf: ti.template())¶

Compute Sky View Factor for all surfaces.

Uses PALM’s methodology (radiation_model_mod.f90): - For upward surfaces: vffrac_up = (cos(2*elev_low) - cos(2*elev_high)) / (2*n_azim) - For vertical surfaces: vffrac_vert = (sin(az2) - sin(az1)) * elev_terms / (2*pi)

where az is measured relative to surface normal and elev_terms accounts for the elevation integration.

Parameters:

surf_pos – Surface positions (n_surf, 3)
surf_dir – Surface directions (n_surf,)
is_solid – 3D field of solid cells
n_surf – Number of surfaces
svf – Output SVF values (n_surf,)

compute_svf_with_canopy(surf_pos: ti.template(), surf_dir: ti.template(), is_solid: ti.template(), lad: ti.template(), n_surf: taichi.i32, ext_coef: taichi.f32, svf: ti.template(), svf_urban: ti.template())¶

Compute SVF including canopy absorption.

Parameters:

surf_pos – Surface positions
surf_dir – Surface directions
is_solid – 3D solid field
lad – 3D Leaf Area Density field
n_surf – Number of surfaces
ext_coef – Extinction coefficient
svf – Output SVF with canopy (n_surf,)
svf_urban – Output SVF without canopy (n_surf,)