DXF Import
Import geometry from DXF drawings.
JW Slope imports geometry from DXF drawings. DXF import is geometry only: it brings in linework and surfaces that you then classify into model entities and assign materials to. No materials, loads, or other model data are read from the DXF, and there is no DXF export.
How import works
DXF files are parsed in a web worker so the interface stays responsive on large drawings. (If web workers are unavailable, parsing falls back to the main thread.) The worker performs two operations: parsing the DXF source and, where applicable, generating section cuts from 3D surfaces.
Sanitization
DXF files vary widely in quality, so the parser sanitizes the input in stages:
- A preflight pass assesses structural risk (entity count, vertex density, extended-data volume).
- If needed, extended entity data (XData) is stripped from entities — including from SEQEND records.
- If a full parse still fails, a quick-view fallback reduces the file to its minimal drawable geometry (lines, polylines, points, arcs, circles, splines, ellipses, 3D faces, and solids) and discards everything else.
Building a 2D model
Supported entities — LINE, POLYLINE, LWPOLYLINE, SPLINE, ARC, CIRCLE, ELLIPSE, 3DFACE, and SOLID — are extracted as curves and flattened to 2D using a best-fit plane through the geometry. Closed curves (those flagged closed, or whose first and last points coincide) are detected as candidate regions.
Imported curves arrive unclassified (tagged as tools). You then assign each curve to a model role in the import dialog:
| Assign to | Result |
|---|---|
| External | The external boundary. |
| Material | A material boundary. |
| Water Table | The water table line. |
| Piezo Line | A pore-pressure line. |
| Weak Layer | A weak-layer path. |
| Support | A ground support (uses the first two points). |
Section cuts from 3D surfaces
JW Slope can extract a 2D section from a 3D triangulated surface in the DXF. The 3D surface is taken from 3DFACE / SOLID entities, or built by Delaunay triangulation of the curve points. A cut plane is intersected with the surface mesh — and with any coplanar linework — to produce 2D polylines, which are then stitched into continuous paths by matching endpoints. This lets you generate a 2D analysis section directly from a 3D model surface.
Notes and limitations
- Geometry only. Materials and loads are never imported. Curves you classify as Material are assigned from JW Slope's material catalog after import.
- No automatic color-to-material mapping. Entity colors and source layers are preserved (the source layer name can appear in a curve's name for reference), but they are not used to assign geometry roles or materials automatically — classification is done manually in the import dialog.
- No DXF export. DXF support is import-only.
After importing geometry, define materials, water, loads, and analysis settings as you would for any model — see the Quick Start.