CAD Trace

Convert imported DWG geometry to native Revit detail or model lines. Each DWG layer is mapped to a Revit line style, with fuzzy auto-suggestion that recognizes AIA naming conventions. Save mapping presets for repeatable workflows across projects.

Location

Modeling panel > slideout > CAD Trace

How to Use

1. Click CAD Trace in the Modeling slideout
2. Select an imported DWG instance in the view
3. The mapping window opens with all DWG layers listed
4. Review the auto-suggested line styles and adjust as needed
5. Toggle layers on/off with the checkboxes
6. Choose Detail Lines or Model Lines output mode
7. Click Convert to create native Revit lines

Layer Mapping

Each DWG layer is automatically matched to the closest Revit line style using fuzzy name matching. The matcher strips AIA discipline prefixes (A-, S-, M-, E-, P-) and IMPORT- prefixes before comparing names.

You can override any suggestion by selecting a different style from the dropdown.

Presets

Save your layer mappings as presets for reuse:

• Save: Save current mappings to a named preset
• Load: Select a preset from the dropdown to apply it
• Import/Export: Share presets as JSON files between machines
• Built-in presets: "AIA Standard" and "Simple 1:1" are included

Text Extraction

When a DXF source file is available, enable Extract Text to convert TEXT and MTEXT entities into Revit TextNotes:

• Text position, height, and rotation are preserved
• MTEXT formatting codes are stripped automatically
• Use Browse DXF... if the source file path cannot be resolved automatically

OCR Text Extraction

When no DXF source file is available (embedded DWG or missing file), enable Use OCR for text to recover visible text directly from the view using Windows built-in OCR.

Requirements

• Windows 10 or later (uses the built-in Windows.Media.Ocr engine)
• English language pack installed (most Windows installations include this)
• If the checkbox is grayed out, your system does not support OCR

How It Works

1. Check Use OCR for text in the CAD Trace window
2. Click Convert
3. The tool exports the active view to a high-resolution bitmap (4096px, 300 DPI)
4. Windows OCR scans the image for text
5. The OCR Review Window opens showing detected text

Review Window

Before any TextNotes are created, you can review the OCR results:

• Edit text - Click the Text cell to correct OCR misreads
• Exclude items - Uncheck rows to skip false positives (dimension fragments, partial words)
• Accept - Create TextNotes from the checked items
• Skip All - Discard all OCR results

The Source column shows OCR or DXF when both extraction methods are active.

Combined DXF + OCR

You can enable both Extract Text (DXF) and Use OCR for text simultaneously. The review window shows results from both sources with a Source column to distinguish them. This captures text that exists in the DXF file alongside rasterized annotations only visible on screen.

Edge Cases

• Crop region disabled - OCR still runs but text positioning may be less accurate. A warning message is shown.
• No text found - If OCR detects nothing, the status bar reports it and no review window opens.
• 3D views - OCR works on any view type that can be exported to an image.
• Large text count - The review window handles up to several hundred items without performance issues.

OCR in Presets

The OCR preference is saved in presets. Loading a preset with OCR enabled will check the checkbox automatically (if OCR is available on the machine).

Supported Geometry

• Lines
• Arcs
• Polylines (decomposed into line segments)
• NurbSplines (tessellated)
• Ellipses (tessellated)

Tips

• Zero-length curves are automatically filtered
• For large DWGs (50,000+ entities), a confirmation dialog appears
• Conversion runs in a single undo-able transaction
• Cancel mid-conversion to keep partially created lines
• Use Hotload (DevTools) after modifying library code

Last updated: 2026-03-31