BIM to Schedule 4D Integration

Technical Implementation

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


class LinkStatus(Enum):
    LINKED = "linked"
    UNLINKED = "unlinked"
    PARTIAL = "partial"


@dataclass
class ScheduleActivity:
    activity_id: str
    activity_name: str
    start_date: date
    end_date: date
    duration_days: int
    wbs_code: str
    predecessors: List[str] = field(default_factory=list)


@dataclass
class BIMElement:
    element_id: str
    element_name: str
    category: str
    level: str
    zone: str
    volume: float = 0
    area: float = 0


@dataclass
class BIMScheduleLink:
    link_id: str
    activity_id: str
    element_ids: List[str]
    link_type: str  # install, remove, temporary
    status: LinkStatus


class BIMSchedule4D:
    def __init__(self, project_name: str):
        self.project_name = project_name
        self.activities: Dict[str, ScheduleActivity] = {}
        self.elements: Dict[str, BIMElement] = {}
        self.links: Dict[str, BIMScheduleLink] = {}
        self._link_counter = 0

    def import_schedule(self, schedule_data: List[Dict[str, Any]]):
        for act in schedule_data:
            activity = ScheduleActivity(
                activity_id=act['id'],
                activity_name=act['name'],
                start_date=act['start'],
                end_date=act['end'],
                duration_days=(act['end'] - act['start']).days,
                wbs_code=act.get('wbs', ''),
                predecessors=act.get('predecessors', [])
            )
            self.activities[activity.activity_id] = activity

    def import_elements(self, element_data: List[Dict[str, Any]]):
        for elem in element_data:
            element = BIMElement(
                element_id=elem['id'],
                element_name=elem['name'],
                category=elem['category'],
                level=elem.get('level', ''),
                zone=elem.get('zone', ''),
                volume=elem.get('volume', 0),
                area=elem.get('area', 0)
            )
            self.elements[element.element_id] = element

    def create_link(self, activity_id: str, element_ids: List[str],
                   link_type: str = "install") -> BIMScheduleLink:
        if activity_id not in self.activities:
            return None

        self._link_counter += 1
        link_id = f"LNK-{self._link_counter:05d}"

        # Verify elements exist
        valid_elements = [eid for eid in element_ids if eid in self.elements]

        status = LinkStatus.LINKED if valid_elements else LinkStatus.UNLINKED
        if valid_elements and len(valid_elements) < len(element_ids):
            status = LinkStatus.PARTIAL

        link = BIMScheduleLink(
            link_id=link_id,
            activity_id=activity_id,
            element_ids=valid_elements,
            link_type=link_type,
            status=status
        )
        self.links[link_id] = link
        return link

    def auto_link_by_level(self, level: str, activity_id: str):
        """Auto-link all elements on a level to an activity."""
        level_elements = [e.element_id for e in self.elements.values()
                        if e.level == level]
        if level_elements:
            return self.create_link(activity_id, level_elements)
        return None

    def get_elements_for_date(self, target_date: date) -> List[BIMElement]:
        """Get elements that should be visible on a specific date."""
        visible_elements = []
        for link in self.links.values():
            activity = self.activities.get(link.activity_id)
            if activity and activity.start_date <= target_date <= activity.end_date:
                for elem_id in link.element_ids:
                    if elem_id in self.elements:
                        visible_elements.append(self.elements[elem_id])
        return visible_elements

    def get_unlinked_elements(self) -> List[BIMElement]:
        linked_ids = set()
        for link in self.links.values():
            linked_ids.update(link.element_ids)
        return [e for e in self.elements.values() if e.element_id not in linked_ids]

    def get_unlinked_activities(self) -> List[ScheduleActivity]:
        linked_activities = {link.activity_id for link in self.links.values()}
        return [a for a in self.activities.values() if a.activity_id not in linked_activities]

    def get_link_summary(self) -> Dict[str, Any]:
        total_elements = len(self.elements)
        linked_elements = len(set(
            eid for link in self.links.values() for eid in link.element_ids
        ))

        return {
            'total_activities': len(self.activities),
            'total_elements': total_elements,
            'linked_elements': linked_elements,
            'unlinked_elements': total_elements - linked_elements,
            'total_links': len(self.links),
            'link_coverage': round(linked_elements / total_elements * 100, 1) if total_elements > 0 else 0
        }

    def export_links(self, output_path: str):
        data = []
        for link in self.links.values():
            activity = self.activities.get(link.activity_id)
            data.append({
                'Link ID': link.link_id,
                'Activity': activity.activity_name if activity else '',
                'Start': activity.start_date if activity else None,
                'End': activity.end_date if activity else None,
                'Elements': len(link.element_ids),
                'Type': link.link_type,
                'Status': link.status.value
            })
        pd.DataFrame(data).to_excel(output_path, index=False)

Quick Start

bim4d = BIMSchedule4D("Office Tower")

# Import schedule
bim4d.import_schedule([
    {'id': 'A100', 'name': 'Foundation', 'start': date(2024, 1, 1), 'end': date(2024, 2, 28)},
    {'id': 'A200', 'name': 'Structure L1', 'start': date(2024, 3, 1), 'end': date(2024, 4, 30)}
])

# Import elements
bim4d.import_elements([
    {'id': 'E001', 'name': 'Footing F1', 'category': 'Foundation', 'level': 'Foundation'},
    {'id': 'E002', 'name': 'Column C1', 'category': 'Structure', 'level': 'Level 1'}
])

# Create links
bim4d.create_link('A100', ['E001'])
bim4d.create_link('A200', ['E002'])

summary = bim4d.get_link_summary()
print(f"Link coverage: {summary['link_coverage']}%")

Resources

• DDC Book: Chapter 3.3 - 4D BIM