bim-cost-estimation-cwicr

# BIM Cost Estimation with DDC CWICR

Generate accurate cost estimates from BIM models using AI classification and the DDC CWICR construction cost database.

## Business Case

**Problem**: Traditional cost estimation:
- Manual and time-consuming (weeks for detailed estimate)
- Subjective and inconsistent between estimators
- Requires specialized knowledge
- Difficult to update with design changes

**Solution**: Automated BIM-to-cost pipeline:
- Extract quantities directly from model
- AI classifies elements to work items
- Vector search finds matching prices in CWICR
- Complete estimate in hours, not weeks

**ROI**: 80% reduction in estimation time, consistent methodology

## System Architecture

```
┌──────────────────────────────────────────────────────────────────────────┐
│                  BIM TO COST ESTIMATION PIPELINE                          │
├──────────────────────────────────────────────────────────────────────────┤
│                                                                           │
│   ┌─────────┐     ┌─────────┐     ┌─────────┐     ┌─────────────────┐   │
│   │ BIM     │     │ DDC     │     │ AI      │     │ DDC CWICR       │   │
│   │ Model   │────►│Converter│────►│ LLM     │────►│ Vector Search   │   │
│   │.rvt/.ifc│     │         │     │         │     │ (Qdrant)        │   │
│   └─────────┘     └─────────┘     └─────────┘     └─────────────────┘   │
│                        │              │                    │             │
│                        ▼              ▼                    ▼             │
│                   ┌─────────┐    ┌─────────┐         ┌──────────┐       │
│                   │ .xlsx   │    │ Work    │         │ Matched  │       │
│                   │ QTO     │    │ Items   │         │ Rates    │       │
│                   └─────────┘    └─────────┘         └──────────┘       │
│                        │              │                    │             │
│                        └──────────────┼────────────────────┘             │
│                                       ▼                                  │
│                              ┌─────────────────┐                        │
│                              │ COST ESTIMATE   │                        │
│                              │                 │                        │
│                              │ • By element    │                        │
│                              │ • By trade      │                        │
│                              │ • By phase      │                        │
│                              │ • Resources     │                        │
│                              └─────────────────┘                        │
│                                                                           │
└──────────────────────────────────────────────────────────────────────────┘
```

## DDC CWICR Database

```yaml
Database Overview:
  work_items: 78228  # 8 national bases
  resources: 27,672
  languages: 9 (AR, DE, EN, ES, FR, HI, PT, RU, ZH)
  fields_per_item: 85
  embedding_model: BAAI/bge-m3 (1024d)
  vector_db: Qdrant

Collections:
  - ddc_cwicr_ar  # Arabic (Dubai prices)
  - ddc_cwicr_de  # German (Berlin prices)
  - cwicr_en_v3  # English (Toronto prices)
  - ddc_cwicr_es  # Spanish (Barcelona prices)
  - ddc_cwicr_fr  # French (Paris prices)
  - ddc_cwicr_hi  # Hindi (Mumbai prices)
  - ddc_cwicr_pt  # Portuguese (São Paulo prices)
  - ddc_cwicr_ru  # Russian (St. Petersburg prices)
  - ddc_cwicr_zh  # Chinese (Shanghai prices)
```

## Pipeline Stages

| Stage | Name | Description |
|-------|------|-------------|
| 0 | Collect BIM Data | Extract elements from Revit/IFC |
| 1 | Project Detection | AI identifies project type |
| 2 | Phase Generation | AI creates construction phases |
| 3 | Element Assignment | AI maps types to phases |
| 4 | Work Decomposition | AI breaks types into work items |
| 5 | Vector Search | Find matching rates in CWICR |
| 6 | Unit Mapping | Convert BIM units to rate units |
| 7 | Cost Calculation | Qty × Unit Price |
| 7.5 | Validation | CTO review for completeness |
| 8 | Aggregation | Sum by phases and categories |
| 9 | Report Generation | HTML and Excel outputs |

## Python Implementation

```python
import pandas as pd
import numpy as np
from qdrant_client import QdrantClient
from qdrant_client.models import Filter, FieldCondition, MatchValue
from openai import OpenAI
from typing import List, Dict, Optional
from dataclasses import dataclass
import json

@dataclass
class WorkItem:
    """Matched work item from CWICR"""
    cwicr_code: str
    description: str
    unit: str
    unit_price: float
    labor_cost: float
    material_cost: float
    equipment_cost: float
    productivity: float  # units per hour
    currency: str
    confidence: float

@dataclass
class CostLineItem:
    """Single line item in estimate"""
    bim_type: str
    work_item: WorkItem
    quantity: float
    quantity_unit: str
    total_cost: float
    labor_cost: float
    material_cost: float
    equipment_cost: float
    phase: str
    trade: str


class BIMCostEstimator:
    """BIM to cost estimation using DDC CWICR"""

    def __init__(
        self,
        qdrant_url: str,
        qdrant_api_key: str = None,
        openai_api_key: str = None,
        language: str = "EN"
    ):
        self.qdrant = QdrantClient(url=qdrant_url, api_key=qdrant_api_key)
        self.openai = OpenAI(api_key=openai_api_key)
        self.language = language
        self.collection = f"ddc_cwicr_{language.lower()}"

    def get_embedding(self, text: str) -> List[float]:
        """Generate embedding for text"""
        response = self.openai.embeddings.create(
            model="BAAI/bge-m3",
            input=text,
            dimensions=1024
        )
        return response.data[0].embedding

    def search_cwicr(
        self,
        query: str,
        limit: int = 5,
        category_filter: str = None
    ) -> List[WorkItem]:
        """Search CWICR database for