CAD Drawing Operations · Backend MxServiceCode Guide

Scope: server-side CAD drawing processing (Node.js command line: format conversion, data extraction, parametric drawing generation, splitting/merging, batch export). Routing rules: see Entry Guide; frontend operations: see Frontend mxcad Guide.

Contents

• I. What MxServiceCode Is
• II. Program Acquisition & Directory Structure
• III. Local Reference Docs (must read)
• IV. Task → Command Selection Quick Reference
• V. Task → Doc Lookup Guide
• VI. Capability Boundaries

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I. What MxServiceCode Is

MxServiceCode is a standalone Node.js command-line project for processing CAD drawing files on the backend: open/save DWG, format conversion, data extraction, parametric drawing generation, batch cutting by title block frames, merge/compare, PDF export, and so on.

How it works: invoked from the command line, it runs one command and exits — no daemon, no service to start. The entry point is mxapp.js; each run executes one command and prints one line of JSON to stdout; the project ships a built-in Node runtime, so the system Node is not required.

Contents of the backend service zip (contains BOTH the backend service and the format conversion program mxcadassembly — the complete superset; if only the conversion program is needed, download the standalone MxConvert package instead — see the "Link List" in the Entry Guide):

Windows (the backend service zip extracts to a single top-level dir MxServiceCode_TryVersion\, with two subdirectories inside):

MxServiceCode_TryVersion\    ← Top-level dir after extraction (same name as the zip)
├── MxServiceCode\
│   ├── NODE.JS后台程序开发.doc   ← Official tutorial: how to do backend development based on this project (NOT an API doc)
│   ├── MxServiceCode.sln        ← Solution file
│   └── MxServiceCode\           ← Project directory (all commands run here)
│       ├── bin\node.exe          ← Built-in Node runtime
│       ├── Mx2DNode.node         ← Native module (core CAD capabilities)
│       ├── mxapp.js              ← Entry point (command line)
│       ├── package.json          ← npm run build for compilation
│       ├── src\                  ← TS sources (mxcad\ = API classes, sample\ = feature samples, MxCommand.ts = command registration)
│       ├── test.bat              ← Test script
│       ├── empty_template.dwg    ← Blank template
│       ├── A3.dwg / BT.DWG       ← Title block frame / title block sample blocks
│       └── t1.dwg / tree.dwg     ← Test drawings
└── MxCAD\
    └── Release\                 ← Format conversion program directory (mxcadassembly.exe + fonts\ + runtime deps, etc.)

Linux (the backend service zip extracts to a single top-level dir MxServiceCode_TryVersion\, with two subdirectories inside):

MxServiceCode_TryVersion\    ← Top-level dir after extraction (same name as the zip)
├── MxServiceCode\
│   ├── NODE.JS后台程序开发.doc   ← Official tutorial
│   └── MxServiceCode\           ← Project directory (no .sln; the built-in runtime is `node`, not bin\node.exe;
│                                 also contains start_demo_MxServiceCode.sh, start_demo_systemlib_MxServiceCode.sh, Linux启动说明.txt)
└── Linux\
    └── MxCAD\                   ← Format conversion program directory (mxcadassembly + fonts\ + runtime deps, etc.)

II. Program Acquisition & Directory Structure

2.1 Download & Placement (fixed temp path; download once, reuse across sessions)

Download URLs: follow the "Link List" in the Entry Guide (take the "backend service" row for the target machine's platform; the Linux package is built for Ubuntu 20.04 x86_64). Trial version — mind the license expiry.

Fixed temp path: Windows = %TEMP%\MxCAD\, Linux = /tmp/MxCAD/. Follow the check steps in the Entry Guide: first determine what the task needs (conversion program only / backend service needed), then inspect what is in the temp path — nothing there → download the matching zip per need (conversion program only → standalone MxConvert package; backend service needed → MxServiceCode package, which includes the conversion program) and extract it to the temp path; conversion program only present → if only the conversion program is needed, run the expiry check (see "Deployment and Startup Notes") and use it; if the backend is needed, clear and re-download the backend package; backend package already extracted → run the expiry check + integrity verification, and if incomplete, clear and re-download. The temp path MUST be cleared before any re-download (each package has a fixed structure; the backend package is the complete superset). Do not scan other directories on the user's machine; after the system cleans the temp dir, just re-download.

All commands run in MxServiceCode\MxServiceCode (the project directory) under the temp path.

2.2 Basic Usage (Linux first use requires permission setup)

chmod 777 start_demo_MxServiceCode.sh
./start_demo_MxServiceCode.sh     # the script already chmods node, Mx2DNode.node, mxcadassembly, etc.

If it fails, use ./start_demo_systemlib_MxServiceCode.sh instead (uses the native libraries in the systemLib directory).

⚠️ Built-in Node version limitation (tested): bin\node.exe is v10.9.0 and supports CommonJS only — ESM (import syntax / .mjs) throws SyntaxError directly; there is no fetch, no optional chaining, or other newer features. Helper scripts written for the built-in node must use CommonJS (require) + .js; when you need ESM, use the system Node.

III. Local Reference Docs (must read)

Doc	Content	When to read
1.MxServiceCodeCommandReference.md	Full reference for the 12 CLI commands (params/return values/call examples) + fileparam JSON passing + how to register a new command	When calling an existing command
2.Mx2DNodeSecondaryDevAPIReference.md	All backend parametric drawing/data extraction APIs (Mx2DDraw, MxBackstage, McDbDatabase, McDb* entities, selection sets, geometry objects)	When developing a new command / custom logic
3.DeploymentAndStartup.md	Directory structure, invocation, Linux permissions, standalone mxcadassembly calls and expiry check, logs, secondary development workflow	When deploying / troubleshooting

IV. Task → Command Selection Quick Reference

Before calling any existing command, check against this table that "the command's contract covers the requirement" — the command name is NOT the selection criterion. When no existing command covers the task, go straight to secondary development (see the example in section 9 of "Mx2DNodeSecondaryDevAPIReference.md"); do not "try running" a command whose functionality doesn't match.

What you want to do	Which path	Notes
Extract text / block attributes	getcaddata (existing)	⚠️ TEXT + INSERT attributes only, no geometry entities of any kind
Extract polyline vertices on a specified layer	getPolylineTheSpecifiedLayer (existing)	⚠️ The layer name is hardcoded in GetDwgData.ts; to use across drawings you must change the source and recompile
Extract line / circle / other geometry entity data	Secondary development	No existing command; example in section 9 of "Mx2DNodeSecondaryDevAPIReference.md" (modelSpace().getAllEntity() + instanceof McDbXxx)
Extract the layer list	getAllLayer (existing)	Outputs <filename>_layers.json
DWG→mxweb conversion	mxcadassembly standalone call	⚠️ The convert command is deprecated and unusable; the outpath directory must pre-exist
Batch cutting by title block frames	frameCut2 (existing)	⚠️ frameCut (v1) depends on the 1337 service and is unavailable in the standalone edition
Export the whole drawing to PDF	Mx_Custom_ExportPdf (existing)	Auto-scales to the sheet size
Merge multiple DWGs	margeDwg (existing)	Can filter by layer
Compare the block tables of two drawings	compare_dwg (existing)
Parametric drawing (generate a new drawing)	Secondary development (testParamDraw can serve as a starting template)	See sections 2 and 9 of "Mx2DNodeSecondaryDevAPIReference.md"
Read/write extended data (xdata)	Secondary development	mxtest_getxdata is only a debug example (hardcoded paths; do not use in production)

V. Task → Doc Lookup Guide

Task Type	Doc(s) to Read
Calling an existing command (conversion/data extraction/cutting/merge/PDF export/layers/compare)	"MxServiceCodeCommandReference.md"
Secondary development: a new command or custom processing logic	"Mx2DNodeSecondaryDevAPIReference.md" + the project's src\sample\ sample code
Environment deployment / startup failure / Linux permissions / log investigation	"Deployment and Startup Notes"
Format conversion parameters (DWG/DXF/MXWEB/PDF/JPG, cut_dwg, print_to_pdf)	Official "Drawing Conversion Program Tutorial": link
Getting started with backend development	The bundled NODE.JS后台程序开发.doc (teaches development based on this project; not an API doc)

VI. Capability Boundaries (based on hands-on testing of the 1.0 trial version)

Capabilities present

• DWG/DXF open and save
• Format conversion: DWG→mxweb, etc. (via standalone mxcadassembly call; see "Deployment and Startup Notes" section 3)
• Parametric drawing: lines, arcs, circles, ellipses, points, text, MText, images, hatches, blocks, title block frames/title blocks, five dimension types
• Data extraction: text, block attributes, polylines, layers, xdata extended data
• Selection sets and filters (by type/layer/window/crossing)
• Entity editing: properties, xdata, explode, intersectWith, getArea
• Drawing merge (with layer filtering), batch cutting by title block frames, drawing comparison
• Export: PDF, JPG, mxweb (the frontend display format)
• System variable read/write (LTSCALE, etc.)

Development-mode conventions

• New CAD interface features going forward: developed by the AI on top of this project (src\sample\ pattern + Mx2DNode API)
• After modifying the source, you MUST recompile with npm run build (the runtime executes the .js)

Limitations

• The convert command is unusable: its wgh output format is deprecated and the native module has removed writeWebGLFile (running it reports code:-4). The mxcad frontend only accepts mxweb; use mxcadassembly directly for DWG→mxweb (see "MxServiceCodeCommandReference.md" detailed 1)
• The frameCut (v1) command depends on a service on port 1337, which the standalone MxServiceCode does not provide — use frameCut2 instead (it calls mxcadassembly directly and is functionally equivalent)
• Trial version (TryVersion): mind the license expiry and the open-count limit
• Debug commands such as mxtest_getxdata contain hardcoded paths and must not be used directly in production
• The layer filter value of getPolylineTheSpecifiedLayer is hardcoded in the source; modify it for the target drawing before use