Surfaces from CAD: contour lines and TIN in DXF and DWG
Did the terrain arrive as an AutoCAD drawing? Import the DXF or DWG and TopoCurvas builds the surface from the contour lines or the 3D faces (TIN) in the drawing, so you can generate contours, profiles and volumes without surveying again.
Developed by 
What you can import
Contour lines → surface
Takes the polylines with elevation from the layers you choose and builds a TIN mesh, with the contours as mandatory breaklines.
TIN from CAD (3DFACE)
If the drawing already has a TIN of 3D faces, it is imported as is: the CAD triangulation becomes the surface.
Contours from a TIN
With the imported surface you generate new contour lines at the interval you want, with smoothing and elevation labels.
Points, blocks and elevation text
You can also take the points, blocks and elevation text in the drawing as a point cloud.
Layer filter
Choose which layers of the drawing come in, so borders, text or design drawings do not get mixed in.
DXF and DWG
DWG files are converted to DXF inside your browser, without uploading your file to any server.
What the surface is for
Volume calculation
Cut and fill of the surface against another surface, a level or a pad with slopes.
Profiles and sections
Longitudinal profile and cross sections along an alignment drawn on the imported terrain.
3D view and slopes
A 3D terrain model and a slope map with runoff arrows.
Deliverables
DXF with organized layers, sheets with a title block and a PDF report.
How it works
- Open Import and choose the DXF / DWG tab.
- Select the file and the surface type: contour lines or 3D faces.
- Filter the layers you care about and review the mesh.
- Generate contours, profiles and volumes on that surface.
FAQ
What elevation must the contours have?
The polylines must carry their elevation in the drawing (3D polylines or Z on every vertex). If the drawing has flat contours with the elevation only in a text, assign them the elevation in CAD before importing.
Can I calculate the volume between two surfaces?
Yes. The project supports several surfaces and the volume calculation compares one against another, against a level or against a pad.
You may also like
Contour line generator from survey points
Upload the points file from your survey and get contour lines in seconds, on a TIN mesh you can fix by hand so the terrain looks the way it really is.
Learn more →Cut and fill volume calculator
Compare the existing ground against a level, a pad or a design surface and get cut, fill and the material to haul away or bring in, with a report ready to deliver.
Learn more →Export your survey to DXF and ready-to-deliver sheets
Before exporting you see a preview of how it will look in CAD, with the chosen sheet and plot scale, so text stays readable and does not overlap.
Learn more →Try it with your own points
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