A point cloud is a set of points in 3D space that approximates the shape of an object. 3D scanners and lidars usually produce point clouds. Unlike meshes, point clouds have no edges or faces: they store only the coordinates (X, Y, Z) of the points and, optionally, a normal and a color for each point.
Point clouds are characterized by:
- No connectivity between points.
- A structure defined by discrete, independent points.
- A shape that is inferred rather than explicitly defined.
- Optional orientation data (normals) for each point.
Point Cloud in MeshInspector
When you open a point cloud, it appears as a set of points in the viewport. In the Scene tree, its icon is a ring of dots.
Two panels below the Scene tree describe the selected cloud:
- Information shows Object Type (Point Cloud), the size of the bounding box (Local or World), the number of Points and Point Normals (Yes or No).
- Transform lets you scale, rotate and move the cloud in 3D space.
If the file has no normals, MeshInspector says so in a message after opening. If the cloud is very large, the message also says that only part of the points is drawn; the data itself stays complete.
On the Inspect tab you can open Object Info and Points Info; both panels can be open at the same time.
- Object Info shows general information about the selected cloud: its source format, memory use, number of points and bounding box.
- Points Info shows data for a selected point: its coordinates (X, Y, Z), its normal (if there is one) and information about its neighborhood, such as the radius and the number of points in it.
Add normals first
A normal tells which way the surface faces at a point. Normals give the cloud proper shading in the viewport, and some tools, such as Fusion, need them. The normal tools are on the Points tab:
| Tool | What it does | Plan |
|---|---|---|
| Make Normals | Computes a normal for every point | Professional |
| Orient Point Normals | Turns neighboring normals the same way | Professional |
| Flip Normals | Reverses all normals of the cloud | Free |
| Remove Normals | Deletes the normals | Free |
See Make Normals and Orient Point Normals. To see the normals, turn on Normals in the right-click menu of the cloud.
Open a point cloud
Open a file with Home › Open Files or drag it into the window. These formats open as a point cloud:
| Format | Open | Export |
|---|---|---|
| PLY | Yes | Yes |
| XYZ, XYZN | Yes | Yes |
| ASC | Yes | Yes |
| CTM | Yes | Yes |
| CSV | Yes | No |
| PTS | Yes | No |
| LAS, LAZ | Yes | No |
| E57 | Yes | No |
A PLY file opens as a point cloud when it has points but no triangles. A .txt file opens as G-code, not as a point cloud: if it holds X Y Z coordinates, rename it to .xyz first. The full list of formats is in Supported File Formats.
You can also get a point cloud from a mesh with Mesh Edit › Mesh to Points or from a polyline with Lines › Lines to Points (both Professional plan).
What you can do with a point cloud
| Task | Tools |
|---|---|
| Clean up | Points › Select Outliers, Select Boundary Points, Delete Selected, Reduce Noise |
| Thin out | Points › Sample Points |
| Split | Points › To Components |
| Align scans | Transform › Align Manually, Registration, Global Registration |
Turn a point cloud into a mesh
All these tools are on the Points tab:
| Tool | Use it when | Plan |
|---|---|---|
| Points to Mesh | You have one cloud and want a mesh through its points | Professional |
| Alpha Shape | The cloud has gaps; a ball radius sets which gaps are bridged (in the drop-down list of Points to Mesh) | Free |
| Fusion | The cloud has normals; you need an approximate surface rather than a mesh through every point | Professional |
| Terrain to Mesh | The cloud is a terrain with a regular structure | Professional |
| Scans to Mesh | You have two or more scans of one object to merge into one mesh | Free |
| Convex Hull | You need the convex shell around the points | Free |
See Points to Mesh, Fusion and Terrain to Mesh. To connect the points into a line instead, use Points › Points to Lines.
Save a point cloud
- Export saves the selected clouds as .ply, .xyz, .xyzn, .asc or .ctm. Choose .ply, .xyzn or .asc to keep the normals.
- Home › Save Scene saves the whole scene to a MeshInspector scene file (.mru).
Point cloud options in the Scene tree
Right-click the cloud in the Scene tree to change how it is displayed: point size, colors, opacity, normals, bounding box and name. The menu also has the Remove and Clone buttons, and Clone Selection when some points are selected. Every option is explained in Scene Tree Mastery.
