RJP News

3D - Laser Scanning vs Photogrammetry

The architecture industry is embracing digital robotic systems for the layout of buildings and interior fit-outs due to proven financial and time benefits – replacing the inaccurate tape measure, stringline and laser level approach. Many of our projects feature complex designs with curved walls and buildings with prefabricated materials and non-orthogonal spaces.

Traditionally, the layout of building services on site involved working based on the provided paper drawings. These drawings were used in combination with tape measure, levels and grids to identify location points for elements. This is all changing now. We seek to improve efficiency, ensure accuracy and provide quality data control to move forward with projects faster than traditional methods.

Laser scanning (High-Definition Surveying) is a strategy for capturing reality with high-accuracy mapping. We use laser beams to rapidly capture complete detail of the entire building construction project. Capturing 360 photography is important for visualizing projects and detail. Laser scanning and 3D Imaging are similar except there is an accurate position for every pixel. Capturing a project with an accurate position of the building project is called a Point Cloud. Point Clouds act as a 3D repository embedding information where it is intended to be used. Point Clouds were initially used maintaining industrial plants, but is now becoming a main-stream source for the best way to document any construction project throughout its life-cycle. Point Clouds are the segway to Building Information Modeling (BIM) which will be the bridge to robotic and automatic construction processes.

When to use laser scanning and photogrammetry

  • Renovations: most as-builts are inaccurate and incomplete. We can capture reality files to highest degree of accuracy that can be overlaid on existing, working or finished plan.

  • Additions

  • Expansions: Laser scanning is used to aid in creating anything from massing studies to site renderings. Site plans (applied to global coordinates), Floor Plans, Sections and Elevations can effectively be drawn on top of laser data.

  • Restorations

  • Historical Preservation

  • Mechanical, Electrical, Plumbing, Structural Steel

  • Construction Phases

  • Infrared/Thermal Inspections

  • Pre-construction coordination

  • Pre-drywall

  • Pre-ceiling

  • Pre-slab – quickly assess flatness of concrete floors to calculate the extents of any areas that need to be adjusted and accurately. Coloring the point clouds based on elevation determines volume metrics or high and low areas in the pour. This data can be uploaded to a total station to be staked out in the field.

  • As-built QA

  • As-designed model and drawing comparison

  • Archived records – milestones to manage and maintain building

  • Pre-Fab Components – HVAC, structural steel, floors, and rebar in the concrete slabs with actual installation time record. This information is used to verify components are installed in the correct place.

  • Design revisions – problem identification to avoid future conflicts

  • Construction logistics – Point Cloud can also be used to create paths with the correct clearances to remove equipment from the site once construction is complete

Compare newly constructed work against the as-designed model or drawings. Re-work accounts for 12 to 15% off the cost of construction. With laser scanning, the ability to catch conflicts before they happen can reduce rework to 1% to 3% keeping the project on schedule. We help GCs white-label and transfer data to owners.

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