nx_gcode_extrude_test.nx

nx_gcode_extrude_test.nx -- extrusion math hand-verified against closed-form physics (volume conservation: mass-in == mass-out for incompressible deposit). Reference computation for a 10mm move at standard 0.4mm width + 0.2mm height + 1.75mm filament: filament_radius = 0.875mm filament_xsect = π × 0.875² = π × 0.765625 ≈ 2.405 mm² extruded_volume = 0.4 × 0.2 × 10 = 0.8 mm³ E_delta = 0.8 / 2.405 ≈ 0.3326 mm of filament In Q14: E_delta ≈ 0.3326 × 16384 ≈ 5451 Q14 units. Closed-form invariants: (a) filament_xsect for 1.75mm dia = 2.405mm² ≈ 39408 Q14. Acceptable tolerance: ±2 Q14 units (rounding in radius+π+r²). (b) move_length for (0,0)->(10,0) = 10mm = 163840 Q14. (c) move_length for (0,0)->(0,10) = 10mm = 163840 Q14. (d) move_length for (3,0)->(0,4) (3-4-5 triangle hypotenuse) = 5mm = 81920 Q14 NOTE: Q14 sqrt has small rounding error; accept ±2. (e) E_delta for the standard move = ~5451 Q14. (f) E_delta scales linearly with move length: 20mm move = 2× E_delta of 10mm move. (g) E_delta is 0 for zero-length move. (h) Zero filament_xsect returns 0 (defensive, not crash). expect_exit: 0 license_tier: ORIGINAL