Jerry
97 lines
3.4 KiB
Python
97 lines
3.4 KiB
Python
"""NACA 0016 propeller blade with exact BSpline FreeCAD translation.
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Run from the repository root with:
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uv run python examples/09_naca0016_blade_freecad.py
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Generated files:
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examples/out/naca0016_blade/naca0016_blade.model.json
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examples/out/naca0016_blade/naca0016_blade.step
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examples/out/naca0016_blade/naca0016_blade.fcstd
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The NACA section generator starts from sampled airfoil points. The evolve helper
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fits those samples into exact cubic B-spline control data before calling
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`make_spline_rwire(...)`, so the exported model JSON and FreeCAD document contain
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exact B-spline payloads rather than sampled-point spline approximations.
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"""
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from __future__ import annotations
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import argparse
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import json
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from pathlib import Path
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import simplecadapi as scad
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DEFAULT_OUTPUT_DIR = Path("examples/out/naca0016_blade")
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DEFAULT_FREECAD_CMD = Path("/Applications/FreeCAD.app/Contents/Resources/bin/freecadcmd")
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def build_blade(output_dir: Path, *, freecad_cmd: Path | None = DEFAULT_FREECAD_CMD) -> dict:
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output_dir.mkdir(parents=True, exist_ok=True)
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model_json_path = output_dir / "naca0016_blade.model.json"
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step_path = output_dir / "naca0016_blade.step"
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fcstd_path = output_dir / "naca0016_blade.fcstd"
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with scad.GraphSession() as session:
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blade = scad.make_naca_propeller_blade_rsolid(
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blade_length=4.0,
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root_chord=1.25,
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tip_chord=0.35,
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total_twist_angle=36.0,
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num_sections=6,
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)
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blade = scad.apply_tag(blade, "role.naca0016.blade")
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model_json = scad.export_model_json(session)
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payload = json.loads(model_json)
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model_json_path.write_text(model_json, encoding="utf-8")
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scad.export_step(blade, str(step_path))
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bspline_nodes = [
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node for node in payload["graph"]["nodes"] if node.get("op") == "make_spline_redge"
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]
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loft_nodes = [node for node in payload["graph"]["nodes"] if node.get("op") == "make_loft_rsolid"]
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control_counts = [len(node["params"].get("control_points", [])) for node in bspline_nodes]
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knot_counts = [len(node["params"].get("knots", [])) for node in bspline_nodes]
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print("graph_nodes", len(payload["graph"]["nodes"]))
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print("leaf_ids", payload["leaf_ids"])
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print("bspline_section_nodes", len(bspline_nodes))
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print("loft_nodes", len(loft_nodes))
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print("bspline_control_counts", control_counts[:6])
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print("bspline_knot_counts", knot_counts[:6])
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print("volume", round(blade.get_volume(), 6))
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print("wrote", model_json_path)
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print("wrote", step_path)
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if freecad_cmd is not None and freecad_cmd.exists():
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scad.translator.freecad_translator.translate_model_json_to_fcstd(
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model_json,
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str(fcstd_path),
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document_name="NACA0016Blade",
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freecad_cmd=str(freecad_cmd),
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)
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print("wrote", fcstd_path)
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else:
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print("skipped_fcstd", "FreeCADCmd not found")
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return payload
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def main() -> None:
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parser = argparse.ArgumentParser(description=__doc__)
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parser.add_argument("--output-dir", type=Path, default=DEFAULT_OUTPUT_DIR)
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parser.add_argument(
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"--freecad-cmd",
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type=Path,
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default=DEFAULT_FREECAD_CMD,
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help="FreeCADCmd path used to write .fcstd; skipped if the path does not exist.",
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)
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args = parser.parse_args()
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build_blade(args.output_dir, freecad_cmd=args.freecad_cmd)
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if __name__ == "__main__":
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main()
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