BIM to Schedule 4D Simulation

Technical Implementation

python
import pandas as pd
from datetime import date, datetime
from typing import Dict, Any, List
from dataclasses import dataclass, field
from enum import Enum


class SimulationStatus(Enum):
    SETUP = "setup"
    READY = "ready"
    RUNNING = "running"
    COMPLETE = "complete"


@dataclass
class TimeSlice:
    slice_date: date
    visible_elements: List[str]
    active_activities: List[str]
    completed_activities: List[str]


@dataclass
class Simulation4D:
    simulation_id: str
    name: str
    start_date: date
    end_date: date
    interval_days: int
    status: SimulationStatus
    time_slices: List[TimeSlice] = field(default_factory=list)


class BIMSchedule4DSimulation:
    def __init__(self, project_name: str):
        self.project_name = project_name
        self.elements: Dict[str, Dict[str, Any]] = {}
        self.activities: Dict[str, Dict[str, Any]] = {}
        self.links: Dict[str, List[str]] = {}  # activity_id: [element_ids]
        self.simulations: Dict[str, Simulation4D] = {}

    def add_element(self, element_id: str, name: str, category: str, level: str):
        self.elements[element_id] = {
            'id': element_id, 'name': name, 'category': category, 'level': level
        }

    def add_activity(self, activity_id: str, name: str, start: date, end: date):
        self.activities[activity_id] = {
            'id': activity_id, 'name': name, 'start': start, 'end': end
        }

    def link_elements(self, activity_id: str, element_ids: List[str]):
        self.links[activity_id] = element_ids

    def create_simulation(self, name: str, start: date, end: date,
                         interval_days: int = 7) -> Simulation4D:
        sim_id = f"SIM-{len(self.simulations) + 1:03d}"
        simulation = Simulation4D(
            simulation_id=sim_id,
            name=name,
            start_date=start,
            end_date=end,
            interval_days=interval_days,
            status=SimulationStatus.SETUP
        )
        self.simulations[sim_id] = simulation
        return simulation

    def generate_time_slices(self, sim_id: str):
        if sim_id not in self.simulations:
            return

        sim = self.simulations[sim_id]
        sim.time_slices = []
        current = sim.start_date

        while current <= sim.end_date:
            visible = []
            active = []
            completed = []

            for act_id, act in self.activities.items():
                if act['end'] < current:
                    completed.append(act_id)
                    if act_id in self.links:
                        visible.extend(self.links[act_id])
                elif act['start'] <= current <= act['end']:
                    active.append(act_id)
                    if act_id in self.links:
                        visible.extend(self.links[act_id])

            slice = TimeSlice(
                slice_date=current,
                visible_elements=list(set(visible)),
                active_activities=active,
                completed_activities=completed
            )
            sim.time_slices.append(slice)

            from datetime import timedelta
            current += timedelta(days=sim.interval_days)

        sim.status = SimulationStatus.READY

    def get_slice_at_date(self, sim_id: str, target_date: date) -> TimeSlice:
        if sim_id not in self.simulations:
            return None
        sim = self.simulations[sim_id]
        for slice in sim.time_slices:
            if slice.slice_date == target_date:
                return slice
        return None

    def export_simulation(self, sim_id: str, output_path: str):
        if sim_id not in self.simulations:
            return
        sim = self.simulations[sim_id]
        data = [{
            'Date': s.slice_date,
            'Visible Elements': len(s.visible_elements),
            'Active Activities': len(s.active_activities),
            'Completed': len(s.completed_activities)
        } for s in sim.time_slices]
        pd.DataFrame(data).to_excel(output_path, index=False)

Quick Start

python
sim = BIMSchedule4DSimulation("Office Tower")

sim.add_element("E001", "Footing", "Foundation", "B1")
sim.add_activity("A100", "Foundation", date(2024, 1, 1), date(2024, 2, 28))
sim.link_elements("A100", ["E001"])

simulation = sim.create_simulation("Construction Sequence", date(2024, 1, 1), date(2024, 12, 31))
sim.generate_time_slices(simulation.simulation_id)

Resources

• DDC Book: Chapter 3.3 - 4D BIM