3D-Laser-Scanning-to-Bim-

3D Laser Scanning Vs. Photogrammetry Technology for Construction

3D Laser Scanning is your best option If you need a high level of accuracy across a vast area. But if you’re capturing smaller spaces and want less accuracy but more visual photo realism, photogrammetry is a better option. 

Laser scanning is your best option If you need a high level of accuracy across a vast area. But if you’re capturing smaller spaces and want less accuracy but more visual photo realism, photogrammetry is a better option. 

In present days Today, it’s difficult to envisage the world without digital technology. Nevertheless, the physical world is getting designed & constructed using conventional 2D blueprints, which is yet to be seized in a digital setup. This creates a challenge for the AEC (Architectural, Engineering & Construction) professionals to integrate the as built designs into renovation projects.

 

Laser Scanning vs. Photogrammetry

 

What is 3d Laser Scanning?

We have laser scanning on one hand, which has been around for decades. When it finally made its way into building, design, and engineering, there was a lot of excitement about the accuracy and speed of the new technology. Computers have finally improved to the point where they can handle the massive amounts of data that scanners generate, in the form of point clouds. 

The laser scanner works by putting out hundreds of thousands of light pulses and measuring the distance between its location and the objects that are hit by the light pulses. To know more about 3D Laser Scanning software, services and techniques in construction industry. 

Read More About Our 3D Laser Scanning Services & Scan to BIM, we would be Happy to Assist You!

What is Photogrammetry?

Photogrammetry is the technology of calculating, measuring and recording information about physical objects and terrain features through images. The basis of photogrammetry process is triangulation technique.  Triangulation process is a 3D coordinate measuring technique through photographs. Photo maps a 2D image which can further be rendered into 3D world. But how? By converging the intersecting points in space the 3D coordinates are mathematically calculated. Photographs have to be taken from different locations atleast more than two sides called line of sight for more precision. Tips for good photogrammetry images are Field of View, Focus, Exposure.

Parameters of 3D Photogrammetry Accuracy:

Digital transformation with supportive computer aided software accuracy and precision is the core importance in construction. This was not there in analog to optical-mechanical devices. Still few parameters to hold on for accurate photogrammetry services:

  • Good quality and resolution camera.
  • Size of the physical object , surface or structure.
  • Number of photographs taken
  • Geometric layout of the pictures.

What is Photogrammetry used for?

In earlier days photogrammetry was used for topographic mapping. But efficiency of photogrammetry software have swept the benefits beyond imagination. Photogrammetry is used for surveying and mapping. Envisioning to present day scenario

  1. Engineering: Construction projects depend on accurate measurements. Drones are used for taking photographs for building structures. Apart from this 3D rendering is able to project better perspective of building design.
  2. Surveying: Land surveying is used to determine the surface of Earth. Used by land surveyors for accurate measurement, government officials use for demarcating boundaries .
  3. Real Estate: Photogrammetry and drone techniques in collaboration create a visual 3D image of the property. It not only  saves time but also adds cost effectiveness to the building.

From forensic to film industry including entertainment , Sports every sphere is enjoying benefits of photogrammetry in 3d modeling.

Deliverables from Point Cloud to BIM include:

  • 3D BIM Model Creation for Renovation & Extension – 3D Model gets created using BIM (Building Information Modeling), according to point cloud scan to BIM for enhancing transparency & streamlining communication. BIM technology also facilitates quick decision making during the As-Built Phase.
  • As-Built BIM Drawing Preparation – As-Built drawings can be created for Plan, Elevation & Section Sheet. As-Built also provides a comprehensive tool for the planning of future projects, like extension &renovation from laser scan point cloud.
  • 4D BIM Construction Scheduling – 4D BIM is used for construction scheduling of renovation. Point Cloud or 3D laser scanning to BIM Modeling facilitates the revamp of old buildings for creating interest among architects.
  • BIM Facility Management –BIM engineers enable project team members to combine submittals from point cloud scan during project renovation through facility management. Our experts accomplish complete contact records of the project in the required fields.

 

 

Difference Between Photogrammetry and 3D Laser Scanning:

When there are various tools available to do same task, we must take a step back and evaluate the differences. When deciding between 3D laser scanning and photogrammetry, accuracy, speed, cost, scale, and the end application of the 3D data must all be taken into account. 

We have defined the difference below 

3D Laser Scanning 

3D Photogrammetry 

Benefits: 

Benefits: 

·       Most scanners have an accuracy of less than a quarter of an inch. 

·       Accuracy in huge areas 

·       The error rate is set based on the equipment’s capability. 

·       After the targets are put and the scanner is begun, the procedure is automated, which reduces the potential of user error. 

·       Less time spent on site Auto-extraction / meshing software for point clouds is available. 

·       Less expensive equipment 

·       Because the majority of advancements are made to software, there is no need to purchase new technology to keep up with the times. 

·       Texture visual representation is better. 

Disadvantages: 

Disadvantages: 

·       Physical equipment is generally required to stay up with progress 

·       Excessively expensive to buy. 

·       On highly textured / reflecting surfaces, a fuzzy point cloud appears. 

·       Accuracy is poorer than 3D laser scanners in the large surface area. 

·       Scale restrictions imposed by the need for camera lenses to maintain clarity over vast distances. 

·       Less automated processes allow for more user error — results are highly dependent on the operator’s experience. 

·       More time need to spent on the job site 

·       Auto extraction / meshing software not at all advanced as compared to 3D Laser Scanner 

·       When working with reflective/transparent surfaces, mistakes can be made. 

 

 

 

 

 

 

 

If you need a high level of accuracy across a large surface area, laser scanning is your best option. If you’re capturing smaller spaces and want less accuracy but more visual realistic photo, photogrammetry is a better option. This is why photogrammetry is widely utilized in the entertainment business, such as in the construction of game and film industry. It’s also gaining popularity among archaeologists since it enables for more realistic 3D documenting of specific artefacts at a lower cost than laser scanning. Because of its high level of accuracy over a long distance, laser scanning is better suited to the architecture, engineering, and construction (AEC) industries. AEC specialists are less concerned with photo realistic textures and are much more concerned with accuracy problems over long distances, which can easily pile up to inaccuracies of several feet in a major building when utilising photogrammetry.  

However, even in AEC applications, there are some instances where a certain level of accuracy is acceptable. Mining workers, for example, are turning to photogrammetry for volume predictions as a more cost-effective alternative. Volume estimations of a 20,193 cubic yard pile of gravel were done utilising laser scanning and the latest photogrammetry technologies in a recent case study. The photogrammetry calculation yielded a 1.29 percent inaccuracy, which was deemed acceptable in this situation. 

Benefits of using 3D Laser Scanning to BIM Services:

  • Create as-built 3D BIM models for existing buildings & renovation.
  • 3D models are updated as per the contractors, facility managers, or architect’s prerequisites in a simulated environment.
  • Modeling using point cloud to BIM Services data helps the architecture to make decisions about wanted or unwanted components and structures of the building.
  • Laser Scanning to BIM technology creates a clash simulation analysis for Architectural & MEP services at an initial phase of feasibility review while adding new services.

How to Know Which Is Best Laser Scanning vs. Photogrammetry? 

Photogrammetry and 3D laser scanning are both good in their own right. Consider your budget, the size of the region, and the level of accuracy you require when selecting which is the best fit for your needs. 

Photogrammetry is the way to go when you need to render a landscape as a 3D model for an archaeological survey or movie visuals, for example. Photogrammetry, as opposed to 3D scanning, will deliver better overall outcomes because capturing the reality of the scene is most crucial. Photogrammetry with targets is the best, and possibly only, solution if you require very high precision of specific spots in your scene or on your object. Whereas, 3D scanning is well suited to dense cloud capture of smooth surfaces. 3D scanning is great for capturing big areas with a lot of information.  

For specialised uses, you can combine the two. A forensics team may need to examine surveillance footage to figure out what happened in order to solve a case. A 3D model may be produced and critical evidence extracted from surveillance footage using 3D scanning and photogrammetry. 

Should I Use Laser Scanning or Photogrammetry For 3d Documentation?

It’s difficult to picture a world without digital technology. However, most of the physical world, as you can see, was developed and built using traditional 2D plans and has yet to be preserved in a digital manner. This makes difficult to incorporate as-built designs into re-build or refurbishment projects for AEC professionals. 

Now the question is which technology should we use? Laser Scanning Or, Photogrammetry? Let’s discuss broadly on the topic of Photogrammetry vs 3D Scanning    

Traditional imaging techniques of Photogrammetry supports engineers to piece together images of as-built settings and include GPS data to build interactive 3D models. However, while photogrammetry allows you to cover a broad area rapidly, it does so at a poor level of accuracy. 3D laser scanning, on the other hand, often collects data with a smaller footprint but with a better level of accuracy. Laser scanners capture surface data using a laser beam focused at the surface, frequently with the help of drones or unmanned aerial vehicles (UAVs) (eliminating expensive LiDAR gathering methods), and then convert the data into a point cloud. The point cloud data can then be entered into software like Autodesk ReCap, which quickly turns it into a 3D model or 2D drawing that can be used for future design. Autodesk ReCap turns aerial and object pictures to 3D models in addition to laser scans.