Build Topography in Revit from Rhino/CAD Contours

1. Export contours from Rhino:
   1. In Rhino, select only the topography contour curves.
   2. Use File → Export Selected.
   3. Save as DWG (e.g. topo_lines.dwg) with default settings.
2. In Revit, link the DWG:
   1. Go to Insert → Link CAD.
   2. Select the exported topo_lines.dwg.
   3. Set:
      • Colors: as needed (e.g. Preserve).
      • Units: Auto-Detect or manually choose your modeling units.
      • Positioning: Origin to Internal Origin.
      • Place at: Level 0 (or your base level).
   4. Click Open.
3. Create a Toposolid from the import:
   1. Go to Massing & Site → Toposolid → Create from Import (or Create from CAD).
   2. Select the linked DWG.
   3. In the Layers dialog, check only the layer(s) that contain the topo curves.
   4. Click OK to generate the Toposolid.
4. Edit the topography:
   1. Select the Toposolid.
   2. Click Edit Sketch to change the perimeter outline.
      • Edit or delete contour lines.
      • Ensure the boundary is closed; then click Finish.
   3. Click Modify Sub-Elements to:
      • Select individual points or edges.
      • Change their elevation values.
      • Add points or Split Line to refine the terrain.
5. (Optional) Export the topography back to Rhino:
   1. Select the Toposolid.
   2. Use File → Export → CAD Formats → DWG.
   3. In options (Modify Export Setup):
      • Ensure Solids are exported as ACIS (SAT), not meshes.
   4. Open the resulting DWG in Rhino – it will be editable as a solid built from triangles.

Note: Having the topography as a native Revit element allows landscape consultants to compute cut/fill volumes and makes the model easier to coordinate and update.

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Taught in

• BIM + Computational Workflow · 2023 — original class recording lives there.