OpenCivil3D — survey to CAD, no license required

Import survey points

Column format

sn	E	N	Z	code

Import DXF

Pick the layers that carry your contour / elevation data.

	Layer	Polylines	Points	Z range

Use polyline vertices as surface points (build TIN) Also import POINT entities as survey points

Import trace points

Trace points are drawn on the plan only — they are not added to the surface / TIN, so they never bend your contours. Ideal for gabion walls, kerbs and other features you want to trace. They get their own layer with its own on/off switch. Load from CSV, TXT or XLSX.

Column format

X/E	Y/N	Z/Elev	code

Line from coordinates

Type one X,Y pair per line — or paste straight from AutoCAD: select the line, run LIST, and copy the text output (LINE and POLYLINE both work). Extra columns such as Z are ignored.

Export DXF

Written as DXF R12 — opens in AutoCAD, Civil 3D, BricsCAD, LibreCAD, QCAD… Import layers switched off in the sidebar are left out of the file.