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AutoCAD

AutoCAD interchange is for organizations whose site plans live in .dwg or .dxf files. This lesson covers both directions: moving AutoCAD geometry into Siter for QD analysis, and exporting Siter layers and analysis results back out as DXF (added v0.28) for use in CAD.

Learning objectives

By the end of this lesson you should be able to:

  • Prepare an AutoCAD drawing for import into Siter
  • Recognize which AutoCAD entities translate cleanly and which do not
  • Verify imported geometry against the source drawing
  • Export facility layers and QD arcs as DXF and place them correctly in a CAD drawing

Supported formats​

Siter does not read .dwg or .dxf files directly. Layer import accepts GeoJSON, KML/KMZ, and zipped shapefiles (none of which AutoCAD writes), so the import path for AutoCAD data is an interchange step: export DXF from AutoCAD, convert it to GeoJSON or shapefile in QGIS (see QGIS), then import.

In the outbound direction no interchange step is needed — Siter exports DXF directly, from both the layer export panel and the analysis results exporter.

Pre-import preparation in AutoCAD​

A clean import starts with a clean drawing. Before exporting from AutoCAD:

  • Reduce to relevant entities — turn off layers irrelevant to QD (electrical, utility plans, dimension annotations) so they don't import as noise
  • Convert blocks to geometry — blocks do not survive the conversion; explode them into raw lines and polylines
  • Clean up linework — remove duplicate lines, close polylines that should be closed, fix self-intersections
  • Set drawing units — confirm the drawing's units match the units you'll use in Siter (typically feet for U.S. installations)
  • Establish a reference frame — note the coordinate system the drawing is in (often a local installation coordinate system, sometimes a state plane projection)

Skipping these steps produces a Siter project full of irrelevant geometry, broken polylines, and coordinate-system surprises. The cleanup time spent in AutoCAD pays back ten times over in Siter.

Coordinate system considerations​

AutoCAD drawings are often in a local coordinate system — origin at a survey monument, units in feet, no relation to a global geodetic datum. Siter projects, by contrast, are anchored to a real-world location.

To bridge:

  • If the AutoCAD drawing has known control points with known geodetic coordinates, georeference the drawing in QGIS (see QGIS) before converting
  • If the drawing is already in a known projected coordinate system (e.g., a state plane), assign that coordinate system during the QGIS conversion — Siter reads the coordinate system from the converted file (the shapefile's .prj or the GeoJSON's CRS) and reprojects into the project's spatial reference automatically
  • If neither holds, use placement analysis or manual reference points to register the AutoCAD geometry to Siter's map

For best results, deliver the converted file to Siter in WGS84 (EPSG:4326) or the project's WGS84 UTM zone — those are the best-supported incoming coordinate systems.

Importing into Siter​

There is no AutoCAD-specific import flow: once the drawing is converted to GeoJSON or a zipped shapefile, the import is the standard layer import — see Importing layers for the class module and Layers for the click-by-click steps, including layer type, feature labels, and default feature type options.

Verifying after import​

After import, sanity-check on the map:

  1. Spot-check a few imported features against the source drawing — same shape, same dimensions, same orientation
  2. Confirm the geometry sits at the expected real-world location (not at the AutoCAD origin)
  3. Compare a known distance in the source drawing to the same distance in Siter; they should match within the imagery's precision

If the geometry looks rotated, scaled, or offset, the coordinate system handling did not work. Re-import with corrected settings rather than nudging the imported features into place.

What does not translate​

Through the DXF → QGIS → Siter conversion path:

AutoCAD entitySiter equivalent
Polylines (closed)Polygon features
LinesLine features
PointsPoint features
BlocksMust be exploded to raw geometry first
HatchesNot imported
Text annotationsNot imported as feature attributes
Dimension annotationsNot imported

Exporting from Siter to AutoCAD​

The reverse trip is direct: set File Format to DXF in the layer export panel or the analysis results exporter. The full option reference is in DXF export; the points that matter in a CAD-focused class:

  • Coordinates — the file is in the project's UTM zone, in meters. DXF carries no coordinate-system metadata, so the receiving drawing must already be set up in (or assigned to) the same zone; then the file inserts at 0,0 with scale 1 and lands exactly right
  • Layer structure — one CAD layer per Siter layer, or per analysis result group; layer colors match the on-screen styling
  • Facility data — name, id, and Facility Description ride along as AutoCAD XDATA on each shape, under the application id SITER (keys name=, id=, description=; each record is cut off at 240 bytes). Internal notes are not exported
  • Path facilities — a road drawn as a path facility exports as its polygon only. Since v0.32 there is no _CL centerline layer
  • Union Arcs — a DXF export includes both the individual arcs and the unioned shapes on separate layers; toggle layer visibility in CAD to pick
  • One-way — Siter cannot re-import a DXF; keep the Siter project (or a GeoJSON export) as the editable source

Try it​

Inbound — take a small AutoCAD drawing of a single facility footprint:

  1. In AutoCAD, isolate the relevant geometry, explode any blocks, and confirm units
  2. Export as .dxf and convert to GeoJSON in QGIS, assigning the correct coordinate system
  3. Import into a Siter project
  4. Verify the imported polygon matches the source dimensions and sits at the expected location

Outbound — from a project with analysis results:

  1. Export a facility layer as DXF, then export the analysis results as DXF with Dimension Lines and Union Arcs included
  2. Open both files in a CAD tool, zoom to extents, and confirm the arcs sit correctly around the facilities
  3. Inspect a facility shape's XDATA and find its name and description= record