clash-detection-analysis

干渉検出分析

概要

このスキルは、BIM モデルの干渉を自動検出します。建設前に建築要素間の干渉を特定し、コストのかかる手戻りや遅延を防ぎます。

干渉の種類：

• ハード干渉：要素同士の物理的な交差
• ソフト干渉：クリアランス／許容誤差の違反
• ワークフロー干渉：スケジュール／順序の競合

「設計段階で干渉を検出すれば、現場で修正する場合と比べて、エラーの修正コストを最大10分の1に抑えられます。」

クイックスタート

import ifcopenshell
import ifcopenshell.geom
import numpy as np
from itertools import combinations

# Open model
ifc = ifcopenshell.open("model.ifc")

# Get structural and MEP elements
structural = ifc.by_type("IfcColumn") + ifc.by_type("IfcBeam")
mep = ifc.by_type("IfcPipeSegment") + ifc.by_type("IfcDuctSegment")

# Simple bounding box clash check
settings = ifcopenshell.geom.settings()

def get_bbox(element):
    try:
        shape = ifcopenshell.geom.create_shape(settings, element)
        verts = np.array(shape.geometry.verts).reshape(-1, 3)
        return verts.min(axis=0), verts.max(axis=0)
    except:
        return None, None

def check_bbox_clash(bbox1, bbox2):
    min1, max1 = bbox1
    min2, max2 = bbox2
    if min1 is None or min2 is None:
        return False
    return np.all(max1 >= min2) and np.all(max2 >= min1)

# Find clashes
clashes = []
for s_elem in structural:
    for m_elem in mep:
        bbox1 = get_bbox(s_elem)
        bbox2 = get_bbox(m_elem)
        if check_bbox_clash(bbox1, bbox2):
            clashes.append({
                'element1': s_elem.GlobalId,
                'element2': m_elem.GlobalId,
                'type': 'Structure-MEP'
            })

print(f"Found {len(clashes)} potential clashes")

干渉検出エンジン

コア検出クラス

import ifcopenshell
import ifcopenshell.geom
import numpy as np
import pandas as pd
from dataclasses import dataclass
from typing import List, Dict, Optional, Tuple
from itertools import combinations
from scipy.spatial import cKDTree

@dataclass
class Clash:
    element1_id: str
    element1_type: str
    element1_name: str
    element2_id: str
    element2_type: str
    element2_name: str
    clash_type: str
    distance: float
    location: Tuple[float, float, float]
    severity: str

class ClashDetector:
    """Detect clashes between BIM elements"""

    def __init__(self, ifc_path: str):
        self.model = ifcopenshell.open(ifc_path)
        self.settings = ifcopenshell.geom.settings()
        self.settings.set(self.settings.USE_WORLD_COORDS, True)

        self._geometry_cache = {}
        self.clashes: List[Clash] = []

    def _get_geometry(self, element):
        """Get or compute element geometry"""
        if element.GlobalId in self._geometry_cache:
            return self._geometry_cache[element.GlobalId]

        try:
            shape = ifcopenshell.geom.create_shape(self.settings, element)
            verts = np.array(shape.geometry.verts).reshape(-1, 3)
            faces = np.array(shape.geometry.faces).reshape(-1, 3)

            geom = {
                'vertices': verts,
                'faces': faces,
                'min': verts.min(axis=0),
                'max': verts.max(axis=0),
                'center': verts.mean(axis=0)
            }
            self._geometry_cache[element.GlobalId] = geom
            return geom
        except:
            return None

    def detect_hard_clashes(self, group1_types: List[str],
                            group2_types: List[str]) -> List[Clash]:
        """Detect hard clashes (physical intersections) between two groups"""
        group1 = []
        for ifc_type in group1_types:
            group1.extend(self.model.by_type(ifc_type))

        group2 = []
        for ifc_type in group2_types:
            group2.extend(self.model.by_type(ifc_type))

        clashes = []

        for elem1 in group1:
            geom1 = self._get_geometry(elem1)
            if geom1 is None:
                continue

            for elem2 in group2:
                if elem1.GlobalId == elem2.GlobalId:
                    continue

                geom2 = self._get_geometry(elem2)
                if geom2 is None:
                    continue

                # Bounding box check (fast filter)
                if not self._bbox_intersect(geom1, geom2):
                    continue

                # Detailed check
                intersection = self._check_intersection(geom1, geom2)
                if intersection['intersects']:
                    clash = Clash(
                        element1_id=elem1.GlobalId,
                        element1_type=elem1.is_a(),
                        element1_name=elem1.Name or '',
                        element2_id=elem2.GlobalId,
                        element2_type=elem2.is_a(),
                        element2_name=elem2.Name or '',
                        clash_type='Hard',
                        distance=intersection['distance'],
                        location=tuple(intersection['point']),
                        severity=self._classify_severity(intersection['distance'])
                    )
                    clashes.append(clash)

        self.clashes.extend(clashes)
        return clashes

    def detect_soft_clashes(self, group1_types: List[str],
                            group2_types: List[str],
                            clearance: float = 0.1) -> List[Clash]:
        """Detect soft clashes (clearance violations)"""
        group1 = []
        for ifc_type in group1_types:
            group1.extend(self.model.by_type(ifc_type))

        group2 = []
        for ifc_type in group2_types:
            group2.extend(self.model.by_type(ifc_type))

        clashes = []

        for elem1 in group1:
            geom1 = self._get_geometry(elem1)
            if geom1 is None:
                continue

            for elem2 in group2:
                if elem1.GlobalId == elem2.GlobalId:
                    continue

                geom2 = self._get_geometry(elem2)
                if geom2 is None:
                    continue

                # Check if within clearance distance
                distance = self._min_distance(geom1, geom2)

                if distance < clearance and distance > 0:
                    clash = Clash(
                        element1_id=elem1.GlobalId,
                        element1_type=elem1.is_a(),
                        element1_name=elem1.Name or '',
                        element2_id=elem2.GlobalId,
                        element2_type=elem2.is_a(),
                        element2_name=elem2.Name or '',
                        clash_type='Soft',
                        distance=distance,
                        location=tuple((geom1['center'] + geom2['center']) / 2),
                        severity='Medium' if distance < clearance/2 else 'Low'
                    )
                    clashes.append(clash)

        self.clashes.extend(clashes)
        return clashes

    def _bbox_intersect(self, geom1: Dict, geom2: Dict) -> bool:
        """Check if bounding boxes intersect"""
        return (np.all(geom1['max'] >= geom2['min']) and
                np.all(geom2['max'] >= geom1['min']))

    def _check_intersection(self, geom1: Dict, geom2: Dict) -> Dict:
        """Check for actual geometry intersection"""
        # Simplified check using closest points
        tree1 = cKDTree(geom1['vertices'])
        distances, _ = tree1.query(geom2['vertices'], k=1)

        min_dist = distances.min()

        if min_dist < 0.001:  # Intersection threshold
            intersection_idx = np.argmin(distances)
            return {
                'intersects': True,
                'distance': min_dist,
                'point': geom2['vertices'][intersection_idx]
            }

        return {'intersects': False, 'distance': min_dist, 'point': None}

    def _min_distance(self, geom1: Dict, geom2: Dict) -> float:
        """Calculate minimum distance between geometries"""
        tree1 = cKDTree(geom1['vertices'])
        distances, _ = tree1.query(geom2['vertices'], k=1)
        return distances.min()

    def _classify_severity(self, distance: float) -> str:
        """Classify clash severity"""
        if distance < 0.01:
            return 'Critical'
        elif distance < 0.05:
            return 'High'
        elif distance < 0.1:
            return 'Medium'
        else:
            return 'Low'

    def get_clash_report(self) -> pd.DataFrame:
        """Generate clash report as DataFrame"""
        if not self.clashes:
            return pd.DataFrame()

        return pd.DataFrame([
            {
                'Element1_ID': c.element1_id,
                'Element1_Type': c.element1_type,
                'Element1_Name': c.element1_name,
                'Element2_ID': c.element2_id,
                'Element2_Type': c.element2_type,
                'Element2_Name': c.element2_name,
                'Clash_Type': c.clash_type,
                'Distance_m': c.distance,
                'Location_X': c.location[0],
                'Location_Y': c.location[1],
                'Location_Z': c.location[2],
                'Severity': c.severity
            }
            for c in self.clashes
        ])

    def get_summary(self) -> Dict:
        """Get clash detection summary"""
        df = self.get_clash_report()
        if df.empty:
            return {'total': 0}

        return {
            'total': len(self.clashes),
            'by_type': df['Clash_Type'].value_counts().to_dict(),
            'by_severity': df['Severity'].value_counts().to_dict(),
            'critical_count': len(df[df['Severity'] == 'Critical']),
            'element_types_involved': df['Element1_Type'].unique().tolist() +
                                     df['Element2_Type'].unique().tolist()
        }

干渉セットの設定

一般的な干渉テストセット

# Define common clash test configurations
CLASH_SETS = {
    'structure_vs_mep': {
        'group1': ['IfcColumn', 'IfcBeam', 'IfcWall', 'IfcSlab'],
        'group2': ['IfcPipeSegment', 'IfcDuctSegment', 'IfcCableSegment'],
        'clearance': 0.05,
        'description': 'Structural elements vs MEP systems'
    },
    'piping_vs_hvac': {
        'group1': ['IfcPipeSegment', 'IfcPipeFitting'],
        'group2': ['IfcDuctSegment', 'IfcDuctFitting'],
        'clearance': 0.10,
        'description': 'Plumbing vs HVAC conflicts'
    },
    'doors_clearance': {
        'group1': ['IfcDoor'],
        'group2': ['IfcColumn', 'IfcWall'],
        'clearance': 0.90,  # Door swing clearance
        'description': 'Door opening clearances'
    },
    'electrical_vs_plumbing': {
        'group1': ['IfcCableSegment', 'IfcElectricDistributionBoard'],
        'group2': ['IfcPipeSegment', 'IfcSanitaryTerminal'],
        'clearance': 0.15,
        'description': 'Electrical safety clearance from water'
    },
    'ceiling_vs_mep': {
        'group1': ['IfcCovering'],
        'group2': ['IfcPipeSegment', 'IfcDuctSegment', 'IfcCableCarrierSegment'],
        'clearance': 0.05,
        'description': 'Ceiling clearance for MEP'
    }
}

def run_all_clash_tests(detector: ClashDetector, clash_sets: Dict = None) -> Dict:
    """Run all configured clash tests"""
    if clash_sets is None:
        clash_sets = CLASH_SETS

    results = {}

    for test_name, config in clash_sets.items():
        print(f"Running: {config['description']}...")

        # Hard clashes
        hard = detector.detect_hard_clashes(config['group1'], config['group2'])

        # Soft clashes
        soft = detector.detect_soft_clashes(
            config['group1'],
            config['group2'],
            config['clearance']
        )

        results[test_name] = {
            'description': config['description'],
            'hard_clashes': len(hard),
            'soft_clashes': len(soft),
            'total': len(hard) + len(soft)
        }

    return results

レポートの生成

干渉レポートのエクスポート

def export_clash_report(detector: ClashDetector, output_path: str):
    """Export comprehensive clash report to Excel"""
    df = detector.get_clash_report()
    summary = detector.get_summary()

    with pd.ExcelWriter(output_path, engine='openpyxl') as writer:
        # Summary sheet
        summary_df = pd.DataFrame([{
            'Total Clashes': summary['total'],
            'Critical': summary.get('critical_count', 0),
            'Hard Clashes': summary['by_type'].get('Hard', 0),
            'Soft Clashes': summary['by_type'].get('Soft', 0)
        }])
        summary_df.to_excel(writer, sheet_name='Summary', index=False)

        # All clashes
        if not df.empty:
            df.to_excel(writer, sheet_name='All_Clashes', index=False)

            # By severity
            for severity in ['Critical', 'High', 'Medium', 'Low']:
                severity_df = df[df['Severity'] == severity]
                if not severity_df.empty:
                    severity_df.to_excel(writer, sheet_name=severity, index=False)

    return output_path

def generate_clash_html_report(detector: ClashDetector, output_path: str):
    """Generate HTML report with visualizations"""
    df = detector.get_clash_report()
    summary = detector.get_summary()

    html = f"""
    <!DOCTYPE html>
    <html>
    <head>
        <title>Clash Detection Report</title>
        <style>
            body {{ font-family: Arial, sans-serif; margin: 20px; }}
            .summary {{ background: #f5f5f5; padding: 20px; border-radius: 8px; }}
            .critical {{ background: #ffebee; }}
            .high {{ background: #fff3e0; }}
            table {{ border-collapse: collapse; width: 100%; margin-top: 20px; }}
            th, td {{ border: 1px solid #ddd; padding: 8px; text-align: left; }}
            th {{ background: #4CAF50; color: white; }}
        </style>
    </head>
    <body>
        <h1>Clash Detection Report</h1>

        <div class="summary">
            <h2>Summary</h2>
            <p><strong>Total Clashes:</strong> {summary['total']}</p>
            <p><strong>Critical:</strong> {summary.get('critical_count', 0)}</p>
        </div>

        <h2>Clash Details</h2>
        {df.to_html(index=False) if not df.empty else '<p>No clashes found</p>'}
    </body>
    </html>
    """

    with open(output_path, 'w') as f:
        f.write(html)

    return output_path

クイックリファレンス

干渉の種類	説明	一般的なクリアランス
ハード干渉	物理的な交差	0 mm
ソフト干渉	クリアランス違反	50-150 mm
ワークフロー	スケジュールの競合	該当なし

重大度	距離	必要な対応
重大	< 10 mm	直ちに再設計
高	10-50 mm	優先的に修正
中	50-100 mm	要確認
低	> 100 mm	監視

リソース

• IfcOpenShell：https://ifcopenshell.org
• DDC Website：https://datadrivenconstruction.io

次のステップ

• 時間ベースの干渉分析については 4d-simulation を参照してください
• 検証ワークフローについては bim-validation-pipeline を参照してください
• 要素データについては ifc-data-extraction を参照してください