The plastic return mapping: F = U·Σ·Vᵀ, Σ clamped to [1 − θc, 1 + θs], and the plastic volume ratio Jp takes
what the clamp removed (Jp ← Jp·det Σ / det Σclamped). Compaction stops at maxDensity (Jp ≥ ρ / maxDensity):
past it the clamped values are scaled back so Jp lands on that floor and the rest stays elastic (and pushes back),
since the hardening cap alone would let impacts crush snow to nothing. Jp also stays at most
SNOW_JP_RANGE[1]. On any MPMOps.
The plastic return mapping: F = U·Σ·Vᵀ, Σ clamped to [1 − θc, 1 + θs], and the plastic volume ratio Jp takes what the clamp removed (Jp ← Jp·det Σ / det Σclamped). Compaction stops at
maxDensity(Jp ≥ ρ / maxDensity): past it the clamped values are scaled back so Jp lands on that floor and the rest stays elastic (and pushes back), since the hardening cap alone would let impacts crush snow to nothing. Jp also stays at most SNOW_JP_RANGE[1]. On any MPMOps.