Import Point Clouds and Create Surfaces in FreeCAD

Working with point cloud data in FreeCAD allows you to transform raw 3D scan data into solid, editable CAD geometry. This guide covers the complete workflow for importing point cloud files, cleaning the data, generating a polygon mesh, and converting that mesh into usable surfaces using FreeCAD's built-in Points, Mesh Design, and Reverse Engineering workbenches.

1. Import the Point Cloud Data

FreeCAD supports several standard point cloud formats, including .asc, .pcd, .ply, and delimited text formats like .xyz.

  1. Open FreeCAD and start a new document (Ctrl + N).
  2. Switch to the Points workbench using the workbench dropdown menu.
  3. Go to Points > Import points... or use standard File > Import.
  4. Select your point cloud file and confirm.
  5. If prompted, specify the delimiter used in your file (such as space, comma, or tab) and coordinate order (X, Y, Z). The points will appear in the 3D viewport.

2. Clean and Subsample the Points (Optional)

Large point clouds can slow down processing. You can optimize the cloud before generating a surface:

  • Subsample Points: Select the point cloud in the tree view, navigate to Points > Subsample point cloud..., and choose a spacing value to reduce point density while maintaining overall geometry.
  • Cut and Clean: Use Points > Cut point cloud to remove noise, background elements, or unwanted artifacts from the scanning process.

3. Generate a Mesh from the Point Cloud

Surfaces in CAD are typically built from polygonal meshes derived from the point data.

  1. Switch to the Reverse Engineering workbench.
  2. Select your point cloud object in the tree view.
  3. Click on the Surface from points... tool (or navigate to the mesh reconstruction features).
  4. Choose an algorithm based on your geometry:
    • Delaunay Triangulation: Best for planar or terrain-like surfaces that do not fold over themselves.
    • Poisson or RBF Reconstruction: Suitable for complex, closed, organic, or fully 3D shapes.
  5. Set the max distance and precision parameters, then click OK to generate a mesh object.

Alternatively, you can switch to the Mesh Design workbench, select the point cloud, and use Meshes > Create mesh from geometry... to achieve a similar result.

4. Create Parametric Surfaces

Once you have a mesh, you can construct CAD surfaces (NURBS/B-splines) over the geometry:

  1. In the Reverse Engineering workbench, select the newly generated mesh.
  2. Select the Approximate B-spline surface tool.
  3. Configure the degree of the spline (typically 3 for smooth curvature) and the number of control points to balance accuracy against surface simplicity.
  4. Click OK to fit a B-spline patch to the selected mesh area.

5. Convert to a Solid Shape

If you need a solid body for standard modeling operations (Boolean cuts, extrusions, or technical drawings):

  1. Switch to the Part workbench.
  2. Select the surface or closed mesh.
  3. Go to Part > Create shape from mesh... and define a tolerance (a lower value like 0.1 maintains more fidelity).
  4. Select the newly created shape and navigate to Part > Convert to solid.
  5. Finally, run Part > Refine shape to remove redundant planar edges and clean the final CAD solid.