Engineering drawings are the most information-rich documents in any plant or project. A single P&ID carries equipment tags, instrument loops, line numbers, references to other drawings, and a title block that states exactly what the drawing is and which revision it is. Yet most document management systems treat a DWG file as a sealed box: store it, render a PDF, and leave everything inside untouched.

With the latest CAD-related features in Omega 365 Document Management, we have opened that box. The system now reads native AutoCAD files today, with MicroStation support on the way, harvests the information inside them, connects it to the document and tag registers, and even writes controlled values back into the drawing. Here is what that means in practice.

1. Metadata and tags are read straight from the drawing

When a CAD file arrives in the register, a background job reads the drawing's own structure rather than the rendered text. Administrators map CAD attributes to their business meaning in a simple setup: this attribute is a valve tag, that one is the document number, this one is a reference to another drawing. Each mapping can be narrowed to a specific layer or block, so the same attribute name can mean different things depending on where it sits in the drawing.

CAD Data Extraction Setup – mapping CAD attributes to document fields

From that mapping, the extraction job creates missing tags in the tag register, links every tag to the document, creates hot-spotting links for recognized references, and fills document register fields such as title, revision and release code from the title block. Filling is fill-only: a value already present in the register is never overwritten, and values that do not resolve to a valid register entry are skipped rather than applied.

Every extraction run is logged per document and revision: which mapping rule produced each value, the layer and block it came from, and the outcome. Nothing is guessed, and nothing is hidden.

In the video below you can see the extraction in action, from upload to created tags and filled register fields.

2. Every tag on the drawing becomes a clickable link

Once tags and references are recognized, the drawing opens in the viewer with clickable, color-coded hotspots. Blue means a tag linked to the tag register, green means a reference to another document, and orange means recognized text that is not yet linked. Hover over a hotspot to see the object type, tag number and description; click it to jump to the tag's details, its documents, or, if the tag is connected to a 3D model, straight into the BIM viewer.

P&ID with hotspots and hover information for tag C-104

For native CAD drawings under automatic processing, hotspots are generated in the background as the document is received, so nobody has to run recognition by hand. For scanned or PDF-only drawings, the same engine uses configurable recognition patterns and OCR, and can even suggest patterns by scanning a representative drawing. Hotspots can be switched off at any time, so the drawing is always readable.

In the video below you can see the Omega 365 hot-spotting features in action.

3. External references become managed relationships

An AutoCAD drawing is rarely self-contained. It attaches Xrefs for title frames, base plans and discipline overlays, and the drawing is only complete when those files are available together with it. Omega 365 now reads the drawing's external reference table on upload, matches each reference to a managed document in the same organizational unit, and shows the result as a relationship on the Related Documents tab, in both directions.

Related Documents tab with Xref relationships

That gives you dependency visibility and impact awareness for free: open a title frame or a skid drawing and you immediately see every master drawing that consumes it. References that cannot be matched automatically are not lost; the Xref Mapping dialog lets you connect them to the right document, and the relationship keeps its CAD origin from then on.

The viewer and the PDF rendition both assemble the full reference package. If the current rendition was produced without all referenced content, the viewer shows a clear "Xrefs Missing" warning, and the DWG Rendition Info panel tells you exactly which references were included and which were not. Map the missing ones, regenerate, and the indicators turn green.

Drawing viewer with the "Xrefs Missing" warning badge

In the video below you can see how Xrefs are registered, viewed and mapped.

4. Compare revisions object by object

Reading a full drawing to find what changed between two revisions is slow and error-prone. Omega 365 Document Management now offers four comparison methods from the document card, and for native DWG files the comparison works at object level. Two revisions open side by side in the model viewer, and the analysis identifies new objects, removed objects, geometry changes and moved or restyled objects, each color-coded with counts in a legend. Layers can be shown or hidden per pane so you can focus on what matters.

Object-level CAD comparison with change legend

For PDF renditions and scanned drawings, the visual comparison marks changed areas with cloud markers, and the combined difference view overlays both revisions in one color-coded image. For procedures and specifications, text comparison lists every inserted, deleted and modified passage. The generated difference file can be attached to the document with one click, where it can follow the revision into review to aid reviewers in identifying what changed since the previous revision.

PDF comparison with cloud markers and combined difference overlay

In the video below you can see all comparison methods demonstrated.

5. And the document writes back to the drawing

Reading is only half the story. The document register is the authoritative source for document metadata such as document number, revision, title and release status, and with title block write-back those values are written directly into the native drawing's title block properties. Choose Update CAD File on a DWG document, and a background job writes the current document's values into the mapped properties and stores the result as a new controlled file version. The previous version stays in the file history.

Drawing title block populated with a document's values

The same property mapping serves both extraction and write-back, so what is read from a title block and what is written to it are always aligned. The drawing never becomes a second place to maintain administrative data.

In the video below you can see the title block being updated from a document.

Why this matters

Together, these features change what a drawing is inside the document management system. It is no longer just a file to be stored and rendered, but a structured source of tags, references, metadata and change history. The system harvests that information and feeds it back into the registers, so every drawing makes the whole system richer. Everything runs inside the standard Omega 365 access model, every automatically created tag and relationship carries its origin, and every value written into a drawing comes from validated document data.