nx_softdyn.nx

nx_softdyn.nx -- LIB: SOVEREIGN SECONDARY DYNAMICS ("jiggle physics"), the general solver every animated thing inherits. A driven ANCHOR (a bone from the rig, a weapon mount, a hair root) pulls a mass point through a spring-damper; the mass LAGS under acceleration, OVERSHOOTS when the anchor stops, oscillates, and damps to rest. The SAME solver serves: soft-tissue inertia on a moving body, firearm RECOIL (impulse), cloth and hair sway, vehicle suspension. 100% integer + deterministic -> the same motion replays bit-identically. State stride 6 per point: [px,py,pz, vx,vy,vz] all Q8 (model-units * 256). Semi-implicit Euler: a = K*(anchor-p)/1024 - C*v/1024 ; v += a ; p += v K = stiffness per-1024 (how hard tissue is bound to bone), C = damping per-1024 (how fast wobble dies). Underdamped (C < 2*sqrt(K)) => visible jiggle. Critically/over-damped => rigid, no wobble. A hard displacement CLAMP makes divergence impossible BY CONSTRUCTION (tissue can never fly off the body). license_tier: ORIGINAL