File Formats

PlanCAD works with three file formats: its own native .plancad format for full-fidelity saving, DXF and DWG (both import and export) for interoperability with other CAD software, and PDF for sharing and printing. This page covers the first two; see PDF Export for PDF.

Native Format: .plancad

The .plancad format is PlanCAD's native project format. Files are a compact binary container: a 4-byte PCAD magic header, a version byte, a format byte, followed by a gzip-compressed MessagePack payload. The format is designed to be space-efficient for large floor plans with raster images, while staying forward-compatible via the version byte.

What Is Stored

A .plancad file contains everything needed to reproduce the drawing exactly:

• All entity definitions (geometry, layer assignment, color, linetype, stand number, visibility).
• All layer definitions (name, color, visibility state, lock state).
• Block definitions (reusable symbol libraries embedded in the file).
• Drawing-level settings: active units, snap settings, ortho mode, polar tracking angle, scale factor.
• Pedestrian markers, aisle violation overlays, and the persisted heatmap (format v2+).
• Marker kind (entrance, toilet, food, conference, custom) and weight (low/medium/high) on each pedestrian marker (format v3+).
• Undo history is not persisted — only the current state is saved.

Saving and Opening

Use Ctrl+S to save and Ctrl+O to open. The file chooser is a native OS dialog. PlanCAD does not lock files or create temporary working copies; the file on disk is updated atomically on each save.

Older versions of the format are migrated transparently on read — a v2 file (markers without kind/weight) opens cleanly in a v3-aware build and is upgraded the next time it is saved.

Limitations

• .plancad files from a newer version of PlanCAD may not open correctly in older versions if new entity types or properties were introduced.
• The format is binary — to inspect or repair a file you need to unwrap the PCAD header, gunzip the payload, then decode the MessagePack body.
• The format does not include PDF or raster snapshots. To share a visual preview, export a PDF separately.

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DXF Import and Export

DXF (Drawing Exchange Format) is the standard interchange format for 2D CAD data. PlanCAD can both import and export DXF files, making it straightforward to exchange drawings with AutoCAD, BricsCAD, LibreCAD, QCAD, and similar tools.

Importing DXF

Use File > Import DXF/DWG... to open a DXF file. The importer reads the file and converts entities to PlanCAD's internal representation. The following is preserved during import:

• Layers — all layers in the DXF file are created in PlanCAD, including their color (ACI index or true color) and visibility state.
• Colors — ACI (AutoCAD Color Index) values are converted to the nearest hex color. True-color RGB values are preserved directly.
• Linetypes — standard linetype names (DASHED, DOTTED, CENTER, HIDDEN, etc.) are mapped to PlanCAD's linetype system.
• Entity geometry — coordinates, rotation, and scale are imported as-is.
• Block definitions and inserts — block definitions in the DXF BLOCKS section are imported and block references (INSERT entities) are placed on the canvas.
• Text content — both single-line TEXT and multiline MTEXT entities are imported. MTEXT formatting codes (font changes, bold, color overrides) are stripped; the plain text content is preserved.
• Hatches — HATCH entities are imported, including pattern type and boundary definition.
• Dimensions — DIMENSION entities are imported with their measured geometry.

Supported DXF Entity Types on Import

DXF entity	PlanCAD type
LINE	line
LWPOLYLINE, POLYLINE	polyline
CIRCLE	circle
ARC	arc
ELLIPSE	ellipse
SPLINE	spline
TEXT, MTEXT	text / mtext
DIMENSION	dimension
LEADER	annotation
MULTILEADER	mleader
INSERT	block-insert
HATCH	hatch
WIPEOUT	wipeout
XLINE, RAY	xline

Entities that PlanCAD does not support (3D faces, viewports, OLE objects, etc.) are silently skipped. A console warning is logged for each skipped entity type.

Exporting DXF

Use File > Export DXF... to write the current drawing as a DXF file. The exporter produces an ASCII DXF compatible with AutoCAD 2010 and later (AC1024).

What is included in the export:

• All visible entities (hidden layers are excluded by default, matching the behaviour of "Export visible layers" in the PDF dialog).
• Layer table with names, colors, and linetype assignments.
• Block definitions referenced by any block-insert entity in the drawing.
• Units setting (INSUNITS variable): mm = 4, cm = 5, m = 6.

DXF Export Limitations

• Hatches with complex spline boundaries may be simplified to linear segments.
• Custom stand number labels are exported as text entities placed at the center of the stand, not as a DXF attribute.
• Wipeout boundaries are exported as solid white filled polygons, which may not render as wipeouts in all DXF viewers.
• MText formatting (bold, italic, font changes) set via the MText editor is exported as plain MTEXT content without inline formatting codes.

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DWG Import

DWG is the native binary format used by AutoCAD. PlanCAD can open DWG files via the same File > Import DXF/DWG... dialog. The importer uses the libredwg library to parse the binary format and convert it to DXF-equivalent data, which is then processed through the standard DXF import pipeline.

Supported DWG versions: R2000 through R2018 (versions AC1015 to AC1032). Very old DWG files (R14 and earlier) may not open correctly.

DWG-Specific Behavior

• ACI colors — DWG files encode colors using AutoCAD Color Index values. PlanCAD checks the ACI index before falling back to any true-color value, matching standard CAD display behavior.
• External references (Xrefs) — Xref bindings are not resolved. Entities that reference external files will be absent from the imported drawing.
• Proxy entities — entities created by third-party ARX plugins (furniture libraries, stand numbering add-ins, etc.) cannot be read and are skipped.

When DWG Import Fails

If a DWG file fails to open, try the following:

1. Open the file in AutoCAD, BricsCAD, or another application and re-save it as DXF (R2010 or later). Then import the DXF into PlanCAD.
2. Check that the DWG version is supported. Very new files (saved by AutoCAD 2025 or later) may use a format revision that libredwg has not yet added support for.

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DWG Export

PlanCAD can also write real DWG files via File > Export DWG.... The export pipeline runs entirely in-process — there is no shell-out to an external converter and no third-party binary to install. PlanCAD first serialises the drawing to DXF in memory, then a Rust component (the acadrust crate) parses that DXF and writes the binary DWG bytes to the chosen path.

The DWG output is compatible with AutoCAD and any DWG-aware viewer or editor. All the layer, color, linetype, block, text, hatch, and dimension information that survives DXF export is preserved.

Limitations

• DWG export is desktop-only. The browser build of PlanCAD does not bundle the native converter; in the browser, the export button falls back to saving a DXF instead.
• The same caveats as DXF export apply (see DXF Export Limitations above) — anything that does not round-trip through DXF will not round-trip through DWG either.

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Units and Scale

PlanCAD stores all coordinates in the file in their raw numeric form. The unit label (mm, cm, or m) is stored as metadata and controls how coordinates are displayed in the status bar and properties panel, and how the INSUNITS variable is set in exported DXF files.

When importing a DXF or DWG file that specifies INSUNITS, PlanCAD reads the setting and applies it automatically. If no unit information is present in the file, PlanCAD defaults to millimetres.

If an imported file appears at the wrong scale (e.g. 1000x too large because it was drawn in metres but imported as millimetres), change the units setting in the status bar and use Modify > Scale... to rescale the drawing to match the intended real-world dimensions.