AutoCAD Plant 3D Labeling Script

I need a compact Python routine that plugs straight into AutoCAD Plant 3D and automatically tags every steel beam in my model with unique alphanumeric IDs. The goal is simple: once the script runs, every existing (and newly inserted) beam should display a clean, collision-free label such as B-001, B-002 … without touching columns, braces, or any other elements.

Core requirements
• Detect all beam objects in the current Plant 3D drawing
• Generate alphanumeric codes (prefix + incremental number) and guarantee no duplicates
• Place the tag at a configurable offset so it stays readable in both model and layout views
• Re-run capability: if a beam is deleted or added, the numbering refreshes automatically and gaps are closed or skipped according to standard practice
• Minimal user input—just a prefix, starting index, and optional layer for the labels

Deliverables
1. Well-documented .py file ready to load via Acad’s Script or pyautocad interface
2. A quick read-me showing how to install, set the prefix, and re-launch the renumber command
3. A sample DWG (or a clear step-by-step test case) demonstrating the script annotating at least ten beams

Acceptance test: Running the provided demo should populate every beam with a distinct alphanumeric ID that remains unique after adding, deleting, and renaming any element, with no impact on non-beam objects.

If you’re familiar with ObjectARX, AutoCAD .NET API, or pyautocad wrappers and can keep the code clean, let’s get this automated.