dwg-to-excel

# DWG to Excel Conversion

## Business Case

### Problem Statement
AutoCAD DWG files contain valuable project data locked in proprietary format:
- Layer structures with drawing organization
- Block references with attribute data
- Text annotations and dimensions
- Geometric entities (lines, polylines, arcs)
- External references (xrefs)

Extracting this data typically requires AutoCAD licenses or complex programming.

### Solution
DwgExporter.exe converts DWG files to structured Excel databases offline, without Autodesk licenses.

### Business Value
- **Zero license cost** - No AutoCAD license required
- **Legacy support** - Reads DWG files from 1983 to 2026
- **Data extraction** - Layers, blocks, attributes, text, geometry
- **PDF export** - Generate drawings from DWG layouts
- **Batch processing** - Convert thousands of DWG files

## Technical Implementation

### CLI Syntax
```bash
DwgExporter.exe <input_dwg> [options]
```

### Output Formats
| Output | Description |
|--------|-------------|
| `.xlsx` | Excel database with all entities |
| `.pdf` | PDF drawings from layouts |

### Supported Versions
| Version Range | Description |
|---------------|-------------|
| R12 (1992) | Legacy DWG |
| R14 (1997) | AutoCAD 14 |
| 2000-2002 | DWG 2000 format |
| 2004-2006 | DWG 2004 format |
| 2007-2009 | DWG 2007 format |
| 2010-2012 | DWG 2010 format |
| 2013-2017 | DWG 2013 format |
| 2018-2026 | DWG 2018 format |

### Examples

```bash
# Basic conversion
DwgExporter.exe "C:\Projects\FloorPlan.dwg"

# Export with PDF drawings
DwgExporter.exe "C:\Projects\FloorPlan.dwg" sheets2pdf

# Batch processing all DWG in folder
for /R "C:\Projects" %f in (*.dwg) do DwgExporter.exe "%f"

# PowerShell batch conversion
Get-ChildItem "C:\Projects\*.dwg" -Recurse | ForEach-Object {
    & "C:\DDC\DwgExporter.exe" $_.FullName
}
```

### Python Integration

```python
import subprocess
import pandas as pd
from pathlib imp...