Screen-space 2D-covariance low-pass dilation, in CSS pixels² (the standard 3DGS
anti-aliasing term). Added to the diagonal of the projected covariance Σ_2D
so every splat covers at least ~1 pixel — this prevents extremely anisotropic
splats (near-degenerate, edge-on flat disks, common in imported classical 3DGS
fits) from collapsing to razor-thin sub-pixel spikes. Negligible for the
near-isotropic splats produced by Luxar's own volume fitting. Kept here as the
single source of truth so every GLSL/TSL material + picking constructor uses
an identical default (avoids the uMaxExtentFactor 0.33-vs-1.0 default drift).
Screen-space 2D-covariance low-pass dilation, in CSS pixels² (the standard 3DGS anti-aliasing term). Added to the diagonal of the projected covariance Σ_2D so every splat covers at least ~1 pixel — this prevents extremely anisotropic splats (near-degenerate, edge-on flat disks, common in imported classical 3DGS fits) from collapsing to razor-thin sub-pixel spikes. Negligible for the near-isotropic splats produced by Luxar's own volume fitting. Kept here as the single source of truth so every GLSL/TSL material + picking constructor uses an identical default (avoids the uMaxExtentFactor 0.33-vs-1.0 default drift).