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107 lines
2.9 KiB
107 lines
2.9 KiB
#!/usr/local/bin/python3
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"""Script to generate a fixture of a box falling on a saw."""
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import argparse
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import json
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import pathlib
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import sys
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import numpy
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import shapely.geometry
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import shapely.ops
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from fixture_utils import *
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def generate_fixture(args):
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"""Generate a saw and block."""
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fixture = generate_custom_fixture(args)
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rigid_bodies = fixture["rigid_body_problem"]["rigid_bodies"]
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# Add the saw
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num_teeth = args.num_teeth
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saw_length = 10
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tooth_length = saw_length / num_teeth
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saw_polygons = [
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(numpy.array([[0.0, 0.0], [tooth_length, 0.0], [tooth_length / 2, 1.0]
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]) + [tooth_length * i, 0]).tolist()
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for i in range(num_teeth)
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]
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saw_vertices = numpy.array(saw_polygons).reshape(-1, 2).tolist()
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saw_edges = numpy.array([
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generate_ngon_edges(3) + 3 * i for i in range(num_teeth)
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]).reshape(-1, 2).tolist()
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mass = 10 # Kg
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rigid_bodies.append({
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"vertices":
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saw_vertices,
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"polygons":
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saw_polygons,
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"edges":
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saw_edges,
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"oriented":
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True,
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"position": [0, 2],
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"velocity": [0.0, 0.0, 0.0],
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"is_dof_fixed": [True, True, True],
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"masses":
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numpy.full(len(saw_vertices), mass / len(saw_vertices)).tolist(),
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})
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saw_polygons = [(numpy.array([[0.0, 0.0], [tooth_length / 2, -1.0],
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[tooth_length, 0.0]]) +
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[tooth_length * (i + 0.5), 0]).tolist()
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for i in range(num_teeth)]
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saw_vertices = numpy.array(saw_polygons).reshape(-1, 2).tolist()
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rigid_bodies.append({
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"vertices":
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saw_vertices,
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"polygons":
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saw_polygons,
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"edges":
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saw_edges,
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"oriented":
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True,
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"position": [0, 5],
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"velocity": [0.0, 0.0, 0.0],
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"is_dof_fixed": [False, False, False],
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"masses":
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numpy.full(len(saw_vertices), mass / len(saw_vertices)).tolist(),
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})
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# rigid_bodies.append(generate_walls_body(7, 7, [5, 4.5], 0.1))
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return fixture
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def main():
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"""Parse command-line arguments to generate the desired fixture."""
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parser = create_argument_parser("generate a block falling onto a saw",
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default_gravity=[0, -9.81, 0])
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parser.add_argument("--num-teeth",
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type=int,
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default=10,
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help="number of teeth over a fixed length")
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args = parser.parse_args()
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if args.out_path is None:
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directory = (pathlib.Path(__file__).resolve().parents[1] / "fixtures" /
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"saw")
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args.out_path = (
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directory /
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"interlocking-saws-num-teeth={:d}.json".format(args.num_teeth))
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args.out_path.parent.mkdir(parents=True, exist_ok=True)
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print_args(args)
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fixture = generate_fixture(args)
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save_fixture(fixture, args.out_path)
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if __name__ == "__main__":
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main()
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