nx_gcode_extrude.nx

nx_gcode_extrude.nx -- extrusion-distance math for FDM G-code. Computes how many millimetres of filament must be fed for a given XY move at given line width + layer height to satisfy volume conservation (incompressible deposit): extruded_volume_mm3 = line_width_mm * layer_height_mm * move_length_mm filament_cross_section = π * (filament_radius_mm)^2 E_delta_mm = extruded_volume_mm3 / filament_cross_section Per cardinal feedback-engineering-sciences-bits-up-3d-print-first: this primitive is MATH (geometric volume) + PHYSICS (continuity equation: mass-in == mass-out for incompressible flow). Future physics refinements where this composes: - Rheology: shear-rate-dependent viscosity (PLA at 210°C), pressure-drop through nozzle, max sustainable flow rate - Thermal: melt-zone heat budget bounding max_flow_mm3s - Material science: glass-transition temperature gating bridge fan timing All of those would refine THIS primitive's outputs. v1 ships the volume-conservation core; further physics queued. Coordinate convention: Q14 fixed-point throughout (1 unit = 1/16384). Reusability: this primitive is also valid for CNC paste extruders, food printers, concrete printers, bioprinters -- anywhere a moving nozzle deposits a controlled volume per unit length. Hence runtime/ (multi-purpose), not nishi-print/ (3D-print-specific) hub. Numerical robustness: - Uses nx_isqrt for move-length computation (no float sqrt). - Uses nx_muldiv_i64 for intermediate products that would overflow plain i64 (filament_xsect computation can reach 2^44). license_tier: ORIGINAL