What is a point cloud?

3D point cloud of a petrol station
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A point cloud is a collection of data points in 3D space, each representing a precise location on an object’s surface. These points are defined by X, Y, and Z coordinates, and typically captured using 3D laser scanners.

For example, when scanning a building, each point corresponds to a spot on the walls, windows, or other surfaces. Together, these points form a detailed representation of the object’s exterior.

Contingent on the capture technique and the sensors involved, each point may also contain RGB colour data or intensity information.

Applications of point cloud data

Raw point cloud data is an efficient method for capturing and analysing the shape and form of objects in three dimensions. It provides a basis for 3D modelling, facilitating the creation of meshes, CAD models, and NURBs surface models.

These models form the foundation for applications like quality control and reverse engineering across various industries.

For instance, point cloud data of a manufactured part can be compared to an existing model to identify any deviations. 

It’s also valuable for geospatial surveying and 3D mapping of environments and buildings. Architects can quickly measure distances and angles with millimeter accuracy, and record structural information. Additionally, it serves as a foundation for more complex processes like Building Information Modelling (BIM).

How is a point cloud captured?

The two main techniques used to collect point cloud data are 3D laser scanning and photogrammetry.

Laser scanning

A 3D laser scanner projects infrared laser beams onto a target object or surface and records the time it takes for the beams to reflect back.

Integrating these time measurements with angular data allows the scanner to accurately determine the distance and orientation of each surface point.

By quickly emitting multiple beams from different angles, it gathers a dense array of 3D coordinates, forming a point-cloud representation of the object.

Many of these scanners are equipped with high-resolution cameras, aiding in capturing colour and texture details. By utilising multiple scans from different positions, a comprehensive 3D point cloud can be created, which represents the scanned area.

textured point cloud file of a church

Photogrammetry

Photogrammetry works by capturing multiple photographs of an object or scene from various angles.

These images are then processed using specialized software that identifies common features across the photos.

By analysing the relative positions of these features in different images, the software triangulates their exact spatial positions, constructing a 3D point cloud.

We opt for laser scanning as it provides the highest possible accuracy for our clients. However, we are also able to combine metrology scanning with high-resolution image mapping if you require a photo-realistic 3D model.

Above: A photo-realstic colour and texture 3D model of a goalkeeper glove. This is not a raw photogrammetry point cloud, rather an example of how good it can look after professional post-processing.

3D point cloud processing

Point cloud processing refers to the act of cleaning up the data and optimising it for its intended use case.

There are countless point cloud processing softwares. Which one is right for you depends on the scanner you are using, what tools you need, and the desired output.

Some of the most popular options include:

Note that point cloud files are typically very large, and you’ll require a decent amount of power to work with them.

In many cases, 3D engineers will work with multiple platforms to achieve their end result. For example, our team typically uses a combination of Faro: Scene and Autodesk Revit for laser scanning projects, and Solidworks for smaller CAD modelling jobs.

In terms of basic point cloud processing, the workflow may look something like this:

  • Removing any noise or stray points that distort the data
  • If multiple scans were taken, they need to be aligned to a global coordinate system. This is known as point cloud registration.
  • Creating distinct objects or sections by grouping points together
  • Defining geometric and spatial details
  • Labelling, colour-mapping & 3D modelling

At this stage the data is ready for your end-use or further processing if necessary.

Surface Scan offers an end-to-end solution, from capturing scan data to post-processing and CAD, so you can start working with the deliverables that you need straight away.

How to view a point cloud

colour point cloud data of a house

Though more and more devices are coming with a basic 3D viewer preinstalled, this won’t be sufficient for viewing point cloud files.

Typical point cloud file formats include:

  • XYZ
  • OBJ
  • PTX
  • ASC 
  • FLS
  • PCD
  • LAS
  • PLY
  • FBX
  • E57

Instead, you’ll need to download specialist software. Any of the post-processing platforms we mentioned earlier will do the trick.

However, if you only wish to view the file and don’t want to pay for anything unnecessary, there are a few options.

Free point cloud viewers

  • CloudCompare – CloudCompare is an open-source 3D point cloud and mesh processing software compatible with most common point cloud formats.
  • Autodesk ReCap – Autodesk offers a free 30-day trial of their Autodesk ReCap pro software which features premium tools for viewing and editing point clouds.
  • usBIM – This free online point cloud viewer by ACCA Software lets you view and manage point clouds of any size in many different formats.

Point cloud vs 3D mesh

While point clouds represent objects by collecting a vast number of individual data points, 3D mesh models are created by connecting these points to form a continuous surface.

STL mesh of a shower component

In essence, a 3D mesh is a collection of vertices, edges, and polygonal faces that define the geometry and structure of an object.

Mesh models are more suitable for applications requiring detailed surface information and provide a cleaner model for visualisation.

Examples include:

  • 3D Printing
  • Computer-aided design (CAD)
  • 3D Animation & gaming

We provide an STL mesh model as standard for our 3D scanning customers unless a point cloud is specifically requested. We also offer reverse engineering and CAD modelling services to generate auto-surfaced or parametric 3D models.  

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