Overview
Drones have become indispensable tools for reality mapping in AEC. Capturing a 10+ acre site with a laser scanner can take up to 15 days, but drones can do the same job in a 40 min flight. What's not to like?
However, converting drone models into BIM-compatible formats is an important task that must be understood in order to leverage to true power of drones for reality mapping, progress tracking and verifying design vs build.
In this short guide, we will take a look at how you can use a drone to capture your site and transform the drone images into a BIM-compatible point cloud.
Step-by-Step Guide
To create a BIM-compatible point cloud using drone images, you need to break down the task into a sequence of steps:
Capture High-Quality Drone Images of the Site
Process Drone Images into a 3D Model
Convert the 3D Model into a BIM-compatible point cloud.
Let's take a look at those steps one-by-one below:
Step 1. Capture High-Quality Drone Images of the Site
The very first step of this workflow involves capturing high quality images of the target building or site. It's important that these images have the right structure to them.
Random images of the site will not produce good results.
To ensure high-quality data collection, take a look at software like Hammer Missions, which can automate the drone's flight path for you and capture high quality data from the site.
Typically, creating a 3D model of site would require you to fly in a grid or cross-hatch flight patterns taking images with high overlap between them, ensuring that these images can be stitched later into a 3D model.
credit: mining.com
In the image above, every dot represents an image taken by the drone. The green represents the target site and the blue rectangles represent the footprint of the image on the ground.
If you're unsure how this process works with the drone, here's a workflow video which will walk you through the end-to-end process on how to capture a target site using drones:
Step 2. Process Drone Images into a 3D Model
Once you have captured high quality images of the target building or site, you need to now process these images into a high-quality 3D model, so that it can be later exported into BIM-compatible formats.
To do this, you will need a software platform like Hammer Missions which can process the data into a high-quality 3D models. Since the software is completely cloud based and turn-key, all you have to do is upload the data and push a button to create a 3D model.
The technical term for this 3D model is a 'textured-mesh'. This 3D model is generated using a technique called photogrammetry. You can learn more about photogrammetry over here:
Step 3. Convert the 3D Drone Model into BIM-compatible point cloud.
Having generated a high quality 3D model (textured mesh), step 3 of the process requires you to export the 3D mesh into .las file format. This can be done by exporting the 3D model from Hammer Hub software interface or your preferred platform of choice.
Once you have the .las file for your drone 3D point cloud, you can now import into Autodesk Recap.
Once imported, you can now export the 3D point cloud into .rcp format.
This 3D point cloud in the .rcp format is BIM-compatible and can now be imported into tools such as Revit, Autodesk Civil 3D and more.
And that's it! The complete workflow on how you go from raw drone images to a BIM-compatible 3D model of the site or building.
Summary
We hope the above guide was helpful in understanding how to scan-to-BIM using drones.
Hammer Missions is a cloud-based platform where drone data can be processed and visualized in a full 3D environment. This data can also be annotated using AI to accelerate the annotation process, and it can then be shared with other team members or stakeholders within the organization for further review – a great benefit when working with digital twins.
To find out more about using drone data for BIM and digital twins, please contact our team to learn more.
- Team at Hammer Missions