Chances are that you already know the benefits of point clouds to digital construction – but if you don’t, here they are in a nutshell.
Point clouds give you highly accurate data on as-built conditions, which can be used to inform your plans and to document progress of a construction project. The pinnacle of building point clouds into digital construction workflows is to incorporate the data into a BIM plan. Doing so makes your BIM plan far more accurate and valuable to the construction team, as they know their decisions are being made based on the most accurate data possible.
But to make this a reality, you need to use a point cloud software package to get your point cloud data into a usable format. Point clouds themselves are very large files with lots of data, and they usually need to be processed before they can be used in digital construction.
In this blog I want to help you understand the different types of point cloud software out there, and what they all do.
A glossary of common terms
First of all, let’s go through some common terms that you’ll see when choosing point cloud software:
Scan to BIM
Scan to BIM is the process of taking point cloud data generated by LiDAR scanners and turning it into a BIM plan. This is the most common use of point cloud data in digital construction, and arguably one of the most valuable given then centrality of BIM plans to construction projects.
Scan to plan
Similar to scan to BIM, scan to plan is the process of taking point cloud data and turning it into floor plans. This is often more useful for facilities managers, who can then use that floor plan to get a precise picture of their space, and potentially use the data to plan office redesigns.
Mesh models
Mesh models are an output from some point cloud software. Mesh models are made of triangles, which are in turn created from point cloud data. Mesh models are often much smaller than point clouds, making them easier to use.
Segmented mesh
A segmented mesh model is a mesh model that has been classified to show what it is a model of – for instance, a window, door, structural member, and so forth. This makes it more useful in BIM plans. Segmented mesh models have also often had the “noise” deleted from them – data that’s not required for the project – making them even more useful.
A question of process
Whatever way you look at it, if you want to use your scan data in another software package, your point cloud software will have to process that data before it can be used in your construction workflows. This is because point clouds themselves are, as the name implies, a collection of points. Though when you look at the point cloud with your eyes you can easily see features such as doors and windows, the computer doesn’t know which points correspond to a door, a wall, a pipe, and so forth. That’s the role of point cloud software – to turn the point cloud into a collection of defined assets that can be interpreted by CAD software, which are then used to build the BIM model or the floorplan.
At present, there are two main ways of achieving this. One process essentially involves drawing your BIM elements by hand, using your point cloud as a guide. The other involves converting the point cloud into mesh models that can then be used to create BIM plans from.
Maximise time savings
In this blog I’m recommending that you investigate the mesh modelling process, rather than using point clouds as a guide to manually create 3D BIM objects. The reason is that drawing your BIM elements using the point cloud as a guide is still pretty time-consuming – meaning that, if you’re working with large amounts of point cloud data, you may find yourself spending more time processing the point cloud than you’d have spent manually measuring and drawing everything! Working with mesh models is often much faster – not least because the file sizes you’re working with can be 100x smaller than a similar point cloud file, and so load much faster on computers. Mesh models are also often cleaner than point cloud files too, meaning that you only work with relevant data instead of picking through data that might represent rubble, or people, or objects that aren’t useful.
At the same time, automated and intelligent mesh modelling has recently been pioneered as a way to further speed up the process. This means that some point cloud software packages can automatically turn your point cloud data into mesh models that have been classified so they are ready to use in your CAD software to create BIM plans from. With little expertise required to use the system.
Author Bio:
Mark Senior
Mark has a strong background in Building Construction and Land Surveying. He has been at the forefront of significant technology changes in the Geospatial industry over the last 25 years. He is the business director at PointFuse, a leading clash detection software. He has been involved with PointFuse since its conception, shaping its development from bleeding edge technology to the successful commercial solution it is today.
