How to Build an ArchiCAD Mesh from XYZ Data

Aki Olafsson

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How to Build an ArchiCAD Mesh from XYZ Data

ArchiCAD's Mesh is the native element for site topography. Built from real survey points rather than traced contours, it carries accurate levels, stays editable, and exports cleanly to IFC under IfcSite. This is how to get an X, Y, Z point file into a Mesh, and how to make that Mesh usable once it is there.

Import the points: Place Mesh from Surveyors' Data

ArchiCAD builds the Mesh during import. The command is:

File > Interoperability > Place Mesh from Surveyors' Data

It reads .txt and .xyz files. If your data came out of Excel or QGIS as .csv, rename it to .xyz first, because the file browser for this command only lists .txt and .xyz. The parser handles the separators fine once the dialog can see the file.

Prepare the file first:

  • Three numeric columns, Easting (X), Northing (Y), Elevation (Z), separated by spaces, tabs, semicolons or commas.
  • Do not use the same character for the field separator and the decimal marker. Danish or Icelandic exports with commas for both (524310,50, 181200,25, 42,50) will not parse. Use periods for decimals, or switch the delimiter to tabs or semicolons.
  • A header row like X Y Z is tolerated. ArchiCAD skips any row with non-numeric data.

Run the command, pick the file, and set three things in the dialog: unit of measurement, whether the coordinates are absolute or offsets, and the height above sea level reference. Click OK, then click on the floor plan to place the Mesh. It drops relative to wherever you click, not to the Survey Point.

A known quirk: Place Mesh from Surveyors' Data references the Project Base Point (0,0,0), not the Survey Point. Even with the Survey Point set correctly, the Mesh lands relative to the origin. Either pre-offset your XYZ data (subtract the survey origin from every X and Y before renaming), or move the Mesh manually after placement. This is documented on the Graphisoft Community forums.

Keep the geometry near the origin

Georeferenced coordinates contain large numbers (E: 524,310.50). Placing geometry hundreds of kilometres from ArchiCAD's origin causes graphic glitches, clipping and unreliable snapping. Model the building near the Project Base Point, and use the Survey Point only to store real-world coordinates for IFC georeferencing.

Tidy the Mesh display

A new Mesh shows every triangular face in both plan and 3D. Open Mesh Selection Settings (Ctrl+T / Cmd+T) and set two controls:

  • Floor Plan and Section > Outlines > Ridge Selection: Show User Defined Ridges
  • Model > 3D Appearance: All Ridges Smooth

That gives a clean plan and a smooth 3D surface without deleting any level data.

Separate existing ground from proposed grading

Keep the raw import on a locked layer (for example 3D Terrain - Existing). Duplicate it to a 3D Terrain - Proposed layer for any regrading. To cut a building footprint or a retaining structure into the terrain, use Design > Solid Element Operations with Subtraction with Upwards Extrusion, rather than editing the surveyed Mesh directly. This keeps the level change legible and reversible.

If your survey is a DWG with 3D contours

Sometimes the data arrives as 3D contour polylines in a DWG rather than a point file.

  1. Merge the DWG onto a dedicated site story: File > Interoperability > Merge.
  2. Check the contours are truly 3D. Use the LIST command; if the Z values are zero, they are flat 2D lines with elevation labels and the Mesh will come out flat.
  3. Draw a Mesh boundary over the project area with the Mesh tool.
  4. Hold Spacebar and click a 3D contour to trigger the Magic Wand. In the Add New Points dialog, choose Fit to User Ridges for a clean site model.

Set the IFC classification

For OpenBIM handover, select the Mesh, open Classification and Properties, and set the classification to IfcSite. IFC exports then carry the terrain under the correct spatial hierarchy for civil and GIS teams.

FAQ

What is the ArchiCAD command to import XYZ survey data? File > Interoperability > Place Mesh from Surveyors' Data. It reads .txt and .xyz files and builds the Mesh during import.

Can I import a .csv directly? No. Rename it to .xyz first, and make sure it does not use commas as both the field separator and the decimal marker.

Why does my Mesh not align with the Survey Point? Place Mesh from Surveyors' Data references the Project Base Point, not the Survey Point. Pre-offset the data or move the Mesh after placement.

How do I hide the triangulation lines? Mesh Selection Settings: Show User Defined Ridges in plan, All Ridges Smooth in 3D.

Generate ArchiCAD-ready terrain from a map

Topo-grapher exports a georeferenced .xyz file from a drawn site boundary, ready to drop straight into Place Mesh from Surveyors' Data. Draw the area, pick the density, and download lightweight data from authoritative elevation datasets that builds a clean Mesh on import.

See the full ArchiCAD terrain workflow →

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