ExportDXF/docs/superpowers/specs/2026-04-13-remove-api-excel-export-design.md

ExportDXF: Remove API, Export to Excel

Date: 2026-04-13 Status: Draft

Goal

Remove the FabWorks API and database dependencies from ExportDXF. Replace with local file output: DXF files + an Excel workbook (BOM + Cut Templates) that downstream tools like OpenNest can import directly. Make the tool self-contained — no server setup required.

Approach

Merge the feature/fabworks-api branch into master to get its structural improvements (service layer, models, content hashing, EtchBendLines fixes), then remove the API/DB layer and replace with Excel + log file output.

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Output Structure

Output Folder

• Default location: Templates/ folder in the same directory as the source SolidWorks file
• If Templates/ already exists, the export writes into it (see Revision Handling below)

Files Produced

C:\Projects\4321\
├── 4321 A01.SLDDRW              (source drawing)
└── Templates\
    ├── 4321 A01 PT01.dxf
    ├── 4321 A01 PT02.dxf
    ├── 4321 A01 PT03.dxf
    ├── 4321 A01 PT03 Rev2.dxf   (revised file, original kept)
    ├── 4321 A01.xlsx
    └── 4321 A01.log

Excel Workbook

Written with ClosedXML 0.104.2 (same version as OpenNest).

"BOM" sheet — exact copy of the SolidWorks BOM table. All visible columns and rows reproduced as-is. Only present when exporting from a Drawing that contains a BOM table. Part and Assembly exports omit this sheet.

"Cut Templates" sheet — one row per sheet metal part:

Column	Description
Item #	Item number from the BOM or export sequence
File Name	DXF filename stem (no path, no extension)
Revision	Revision number (1 for initial, increments on change)
Thickness	Sheet metal thickness
K-Factor	K-Factor value
Bend Radius	Default bend radius
Content Hash	SHA256 of DXF content (excluding HEADER section)

Present for all export types (Part, Assembly, Drawing).

Log Files

Per-export log: Templates/{prefix}.log

• Timestamped lines: 2026-04-13 14:32:05 [INFO] Exported 4321 A01 PT03.dxf
• Levels: INFO, WARNING, ERROR
• Appends on re-export

App-level log: C:\ExportDXF\ExportDXF.log

• Rolling log capturing all exports across all drawings
• Same format as per-export log

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Filename Format Template

User Interface

A single text box replaces the equipment/drawing dropdowns. The user types a format string that controls DXF and xlsx naming.

Example: 4321 A01 PT{item_no:2}

Supported Placeholders

Placeholder	Description	Example Output
{item_no:N}	Item number, zero-padded to N digits	{item_no:2} → 03
{part_name}	SolidWorks part name	Bracket
{config}	Configuration name	Default
{material}	Material name	AISI 304

Naming Rules

• DXF filename: full template evaluated per part → 4321 A01 PT03.dxf
• Excel filename: literal text before the first placeholder → 4321 A01.xlsx
• Log filename: same stem as excel → 4321 A01.log
• Validation: template must contain {item_no} (or {item_no:N}) to avoid filename collisions
• If the template starts with a placeholder (no literal prefix), fall back to the document name for the xlsx/log filename

Auto-Fill

On document open, the format template text box is auto-filled via IDrawingInfoExtractor.

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Drawing Info Extraction

Interface

public interface IDrawingInfoExtractor
{
    bool TryExtract(string documentName, out DrawingInfo info);
}

public class DrawingInfo
{
    public string EquipmentNumber { get; set; }
    public string DrawingNumber { get; set; }
    public string DefaultTemplate { get; set; }
}

Implementations

DefaultDrawingInfoExtractor — uses the document name as literal prefix, appends the default suffix from app.config (DefaultSuffix setting, default PT{item_no:2}).

Example: document MyPart.SLDPRT → template MyPart {item_no:2} (or with configured suffix)

EquipmentDrawingInfoExtractor — parses the {EquipmentNo} {DrawingNo} pattern from document names in AJ's workplace format. Builds template like 4321 A01 PT{item_no:2}.

Resolution

Extractors are tried in order. First one that returns true wins. Falls back to DefaultDrawingInfoExtractor.

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Revision Handling

When re-exporting to an existing Templates folder:

1. Read the existing xlsx Cut Templates sheet (if present)
2. For each part being exported, compute the DXF content hash
3. Hash matches existing row → skip, leave existing DXF file untouched
4. Hash differs from existing row → write new DXF with revision suffix (e.g., PT03 Rev2.dxf), update the xlsx row with new filename, new hash, incremented revision number
5. New part (no existing row) → write DXF, add new row to xlsx with revision 1
6. Old revision DXF files are kept in the folder as history

The BOM sheet (if present) is fully rewritten from the current drawing's BOM table on each export.

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What We Keep from feature/fabworks-api

• Service layer architecture: DxfExportService, IPartExporter, IDrawingExporter, IBomExtractor
• Models: BomItem, CutTemplate, Item, ExportContext, LogEvent
• ContentHasher utility (SHA256 excluding DXF HEADER section)
• All 9 EtchBendLines submodule fixes (ACadSharp migration, bend detection, degree symbol, etc.)
• Async export flow with cancellation
• View flip decider
• SolidWorks user input disabling during export

What We Remove

• FabWorksApiClient and all API DTOs
• ExportDxfDbContext, EF Core migrations, SQL Server connection string
• NuGet packages: Microsoft.EntityFrameworkCore.SqlServer, Microsoft.EntityFrameworkCore.Tools
• Equipment/Drawing dropdowns from MainForm
• Any FabWorks.Core / FabWorks.Api projects (if present after merge)

What We Add

• IDrawingInfoExtractor interface + two implementations
• Format template text box with placeholder parsing
• ExcelExportService using ClosedXML — reads/writes BOM + Cut Templates sheets
• LogFileService — per-export and app-level log writing
• Output folder logic (Templates folder next to source, revision handling)
• NuGet package: ClosedXML 0.104.2
• DefaultSuffix setting in app.config

UI Changes

• Replace equipment/drawing combo boxes with a single format template text box
• Keep 3 tabs: Log Events, Bill of Materials, Cut Templates
• Keep Start/Stop button
• Keep View Flip Decider dropdown