FreeCAD usage

## Drawing 2D profiles
use sketcher, draw on x-z plane
use constrain
snap to grid
select lines from combo view > task > elements

## Use the script below to get point x,z coordinates, segments
output in the format for *.poly in dynearthrsol2D

import FreeCAD as App
import FreeCADGui as Gui

def convert_lines_to_points():
    points = {}  # Dictionary to store unique points
    connectivity = {}  # Dictionary to store connectivity between points
    point_id = 0  # Start point ID from 0
    connectivity_id = 0  # Start connectivity ID from 0

    # Select the lines you want to convert in the GUI
    lines = Gui.Selection.getSelection()  # Assuming lines are selected

    if lines:
        total_points = 0
        total_segments = 0

        for line in lines:
            segments = line.Geometry  # Get all line segments
            total_segments += len(segments)

            for segment in segments:
                start_point = segment.StartPoint
                end_point = segment.EndPoint

                # Check if start point already exists
                if (start_point.x, start_point.y) in points.values():
                    start_id = next(key for key, value in points.items() if value == (start_point.x, start_point.y))
                else:
                    points[point_id] = (start_point.x, start_point.y)
                    start_id = point_id
                    point_id += 1

                # Check if end point already exists
                if (end_point.x, end_point.y) in points.values():
                    end_id = next(key for key, value in points.items() if value == (end_point.x, end_point.y))
                else:
                    points[point_id] = (end_point.x, end_point.y)
                    end_id = point_id
                    point_id += 1

                # Add connectivity between points
                connectivity[connectivity_id] = (start_id, end_id)
                connectivity_id += 1

        total_points = len(points)

        # Check and assign positions based on connectivity
        for conn_id, (point1_id, point2_id) in connectivity.items():
            point1_x, point1_y = points[point1_id]
            point2_x, point2_y = points[point2_id]
            position = 0
# note that e3 is added by myself. 
            if point1_y == 0 and point2_y == 0:
                position |= 32  # Set bit 5 to 1
            elif point1_y == -10 and point2_y == -10:
                position |= 16  # Set bit 4 to 1
            if point1_x == 0 and point2_x == 0:
                position |= 1  # Set bit 0 to 1
            if point1_x == 100 and point2_x == 100:
                position |= 2  # Set bit 1 to 1

            # Update connectivity with position information
            connectivity[conn_id] = (point1_id, point2_id, position)

        # Print information about the points and connectivity
        print(f"#### node coordinates # npoints ndims 0 0####\n# npoints ndims 0 0 \n#Total Points:\n {total_points} 2 0 0 ")

        # Print points
        print("#PointID, CoordinateX, CoordinateY")
        for point_id, coordinates in points.items():
            print(f"{point_id}  {coordinates[0]}e3  {coordinates[1]}e3 ")

        # Print connectivity with position
        print(f"#### segments ####\n#Total Segments:\n {total_segments} 1")
        print("\n#ConnectivityID, Point1ID, Point2ID, Position")
        for conn_id, (point1_id, point2_id, position) in connectivity.items():
            print(f"{conn_id}  {point1_id}  {point2_id}  {position}")
    else:
        print("No lines selected.")

convert_lines_to_points()