William H. Gordon Associates, Inc.www.whga.com

High-Definition (3D) Laser Scanning

Simply stated, a three dimensional (3D) laser scan (also referred to as a High-Definition scan or point cloud) is like an image from a digital camera, except that each and every pixel can be established in a real world 3D coordinate system. As compared to traditional surveying methods that field identify individual specific points, High-Definition scanning generates intense regions of points. Accordingly, the surveyor, designer, and/or client has subsequent access to a much larger database of information should survey requirements later change or expand.

3D Laser Scanning is utilized to accurately capture and store “as-built” or “existing” information for areas ranging from mechanical plants to ancient monuments. The scanner captures the information from a scanned area in a digital format. Once in that format, the user can view, measure, assess, and totally interact with that area as though they were located within the actual environment. Clients move freely around in this environment, adopt any chosen viewpoint, and zoom in or out to inspect or measure selected detail. The scanner’s “point cloud” is like a visualized 3D model reflecting real world features in an accurate, re-locatable coordinate system.

Laser Scanning services provide a higher level of survey data accuracy with greater field efficiency to meet the diverse needs of architects, engineers, government agencies, contractors, attorneys, etc. Expedited access to field data from the scanner creates the ability to determine specific dimensional requests more quickly and to customize deliverables to meet the clients’ needs without numerous site re-visits.

Benefits

• Gordon can accurately capture and document a building’s interior or exterior to facilitate the architectural design process for building construction or renovation. The scan data provides an alternative to existing documents that may prove incomplete or inaccurate and thus, enhances the designer’s ability to identify component conflicts. Point cloud data can also be utilized in many CAD and visualization software packages to create informative models to give a complete and interactive view of the project. The modeling information can also assist in evaluating other parameters, such as sun shading, sight lines, and relational mass that may have significant project considerations.

• Gordon can accurately capture and document a facility’s information, including mechanical equipment, piping, structural components, treatment works, etc., to establish critical clearances and/or work spaces. Scan data can be compiled in many restricted areas where traditional surveying methods would not be feasible.

• Gordon can accurately capture and document the conditions of existing structures or sites to establish definitive pre-construction conditions. These same procedures can be utilized to establish extensive documentation on historical structures or sites.

WHAT IS 3D LASER SCANNING?

Gordon performed 3D Laser Scanning Services at the National Gallery of Art in 2007.

William H. Gordon Associates, Inc. (Gordon) is recognized as a leading provider of professional consulting services

to public and private sector clients in the Metropolitan Washington, DC region. Founded in Northern Virginia in 1976,

Gordon has assembled civil engineers, land planners, landscape architects, surveyors, and security/law enforcement

professionals located within a regional network of offices to provide comprehensive, multi-disciplined services to

address the needs of government and business.

CAPABILITIES

Site Consulting Services

• Civil Engineering

• Landscape Architecture

• Site Security Consulting

• Sustainable Planning/Design

• Land Planning

• Recreational Facility Planning/Design

Survey & Mapping Services

• Topographic Surveys

• High-Definition Laser Scanning

• Property Mapping Surveys

• Construction Layout

• QA/QC Surveys

• GIS/Database Development

4501 Daly Dr., Suite 200Chantily, VA 20151

301 North Mildred St., Suite 1ACharles Town, WV 25414

“Gordon’s mission is to provide value-added professional consulting services associated with the development and stewardship of land and/or facilities.”

WASHINGTON, DC

TOP20E N G I N E E R I N G F I R M

CONTRUCTION MONITORING

Point Cloud and Photo

Earthworks

Construction may include activities, such as surface grading, bank/slope construction, stockpile/material quantities, and QA/QC requirements. High Definition Surveys utilizing Gordon’s 3D laser scanner achieve precise measurements in a fraction of the time conventional surveys require. Gordon’s High Definition Laser Scanning covers area more thoroughly and quickly and helps address the needs associated with hazardous or complex sites. Delivery of highly accurate and robust topographic data, combined with true color photographic information, ensures a comprehensive picture of the construction activities is established.

Image of point cloud data draped with digital imagery. Gordon performed a High- Definition Survey of this site to obtain an as-built survey of dredge material from Lake Accotink in Fairfax County, VA. Point cloud data can be processed into topographic maps and delivered in a variety of formats, including Microstation. Laser scanning was essential to this project because it kept Gordon personnel out of the dredging areas, while obtaining topographic data that would otherwise be unattainable via traditional survey methods.

Gordon is able to quickly and accurately scan large areas of excavation to monitor soil volumes, such as the dam site shown here.

Digital Terrain ModelStockpile Monitoring

Gordon performed long-term monitoring of this stockpile to provide material quantities. Beginning with a Digital Terrain Model created from a 3D mesh of the point cloud (shown right), contours can be created, and the volume can be calculated in the field once all the data is acquired.

TOPOGRAPHIC SURVEYS

Project: National Gallery of Art

The use of a laser scanner for typical topographic surveys is becoming more common place with the evolution of fast point cloud data collection, 360° field of views and scripting. The scanner can be programmed to scan different parts of the site and point space at each setup using scripts, thus permitting the instrument to work hands-free. Gordon crews utilizing conventional survey equipment, such as robotic total stations, are able to supplement the survey with data such as invert elevations. As a result, HDS has become cost effective in the preparation of topographic and ALTA/ACSM Land Title Surveys. Additionally, the value-added benefit of compiling more data than that of conventional surveying reduces the need for future site visits as the project’s scope evolves.

Located on the block between Constitution Avenue, Madison Drive and 7th and 9th Streets, NW is the Sculpture Gardens of the Smithsonian Institute. Gordon performed a topographic survey of the grounds utilizing both HDS and conventional surveys. Laser scanning provides detailed topography maps and exhibits for clients and stakeholders.

Project: Meyer Elementary School

Gordon’s surveyors performed HDS of this former elementary school grounds as a part of a repurposing and planning project for the DC Office of Property Management. The points from the scanner point cloud can be cleaned of unnecessary noise and augmented with points from a conventional survey to create a 3D surface model and a 2D topographic map, as shown here.

Interior Applications

This two story atrium at the lobby of this building would have been difficult to as-built if not for high-definition scanning. The captured data was used to create and render a 3D model. Three-dimensional models of a building such as this one can provide an accurate base for the creation of a Building Information Model (BIM).

Concrete Floor As-Built

The floor of this new building in downtown Washington DC was constructed with an enormous amount of sag. Gordon’s surveyors are able to capture all the imperfections for structures such as this one, which can then compiled into a surface mesh of each floor. A grid of elevations at five foot intervals was created for the structural design of these corrections. Gordon’s data revealed the sag was as much as 3-inches at the center point of four columns in this building.

ARCHITECTURAL

Exterior Renovation

The capture of infrastructure on existing buildings for architectural design purposes is greatly enhanced through the use of laser scanning. The scanner’s ability to capture data points on surfaces that are otherwise hard to reach or in unsafe locations is invaluable, especially for structures with complex geometry. Most building features are vertical or directly overhead, which provide the line-of-sight and angles conducive for a scanner’s beam. The fact that many buildings may be occupied during survey operations is not problematic since a laser scanner’s dense data capture enables geometry to be complied even when people move through the scanner’s field-of-view.

The client needed a cost effective way to as-built the exposed face of an existing building being completely remodeled. The building exterior was redesigned to be fitted with a new glass curtain wall. The remote measuring capabilities of HDS is extremely cost-effective for most architectural client needs. Gordon surveyors saved the client significant time by performing an HDS to obtain an accurate “as-is” 3D model of the existing columns. In the office, a reference plane was established and measured to the outside column face at each of the 12 stories for engineering of the new glass curtain wall.

Historical Preservation

As a precaution prior to construction of an adjacent high rise building, clients may desire to accurately map elements of the existing building. Gordon’s surveyors performed a HDS of this historical house to capture existing conditions in the event construction activities caused structural damage or marred the exterior of the historical home dating back to the 1800s.

Solution

Wire Frame

A 3D model can be exported as a wire frame mesh to AutoCAD, Microstation or other design software. Additionally, the as-built wire frame can be imported into facility management information systems and other BIM applications.

3D “as-is” models of existing plant systems are utilized in retrofits, revamps, interference checking, or clash detection and reverse engineering. The increased accuracy reduces variances in engineering and construction, helps reduce errors, and eliminates the need for return visits to the project site.

MECHANICAL & INDUSTRIAL

10 Megapixel Image & Point Cloud

Gordon’s high definition 3D laser scanner has a built in 10 mega pixel camera to capture 360° panoramic images. The images can be draped over the scanned point cloud to create realistic 3D ortho imagery and .avi format “fly-throughs”. Point clouds are also applicable for providing “true” dimensions, pipe widths, angles between two planes, and plumbness of walls or columns.

The need for fast and precise measurements and industrial applications is critical. Whether managing existing space, positioning pipes, establishing as-built dimensions or planning new additions, a 3D laser scan provides a timely, permanent record, critical decisions, and panoramic imagery. Typical facilities that benefit from the use of 3D laser scanning include chemical plants, power stations, water works, gas works, factories, and other industrial facilities that may have “clean conditions” rooms.

Utilizing state of the art modeling software, Gordon can create 3D models from the point cloud for rendering surfaces, determining distances/volumes, or locating and identifying objects. This post data collection process includes cleaning unwanted points from the point cloud, segmentation and fitting of the geometric features (e.g., planes, cylinders, cones, spheres).

3D Modeling

Intersection Improvements

Bridge Design

A heavily traveled four lane highway is reduced to two lanes prior to crossing the bridge over the Shenandoah River from Harpers Ferry, WV. Gordon’s engineers needed to design improvements to the intersection of the access road into a section of Harpers Ferry National Park just before the bridge on U.S. Route 340. Gordon surveyors were able to scan the intersection in one day collecting all road features including existing striping without impeding traffic.

Gordon’s scanner team performed a High Definition Survey of this bridge crossing over Interstate 395 in Virginia. Three dimensional models of both bridge surfaces and understructures were able to be scanned in one day from just four positions.

ROADWAY & BRIDGES

Road Surface Repairs

Tunnel Repairs

Gordon employed its Scanstation 2 from the shoulder of Interstate-66 to capture a four lane section of the concrete road surface in dire need of repair. The data was captured in two days during heavy traffic periods, while closing only the highway shoulder. Point cloud data can be used to create line work and surface models for a detailed topographic map of roadway projects such as this one. Additionally, the point cloud and digital imagery can identify all damaged areas for engineering design.

High Definition Surveying utilizing a 3D laser scanner is a fast and safe way to capture as-built information needed for road and bridge design, inspection, and monitoring. The 3D Laser Scanner can be positioned out of the flow of traffic, while providing a 360 degree scan of the roadway, intersection, or bridge. The scans are combined into an accurate 3D model, which is edited to remove scanned vehicles and other “noise” to create the line work and surface model. The scanning technology allows Gordon to employ safe work zones without lane closures or impacting traffic flow.

Gordon obtained detailed point cloud data of a portion of the Interstate 395 bridge-tunnel in Washington, DC. Point cloud data was used to dimension and design replacement granite panels of the bridge-tunnel facades.

3D Model from Point Cloud

3D Model - Point Cloud Overlay

The 3D model helps enhance the visual effects of the point cloud data.

The data can be modeled into a 3D rendering and exported to other software for additional animation programs.

FORENSICS

Crime Scene Preservation

Point of View Imagry and Animation

Most forensic professionals agree that the single most valuable benefit gained from the technology is the ability for investigators to virtually return to the crime scene and extract out additional measurement and viewpoint data. This can be done days, weeks, or years later; long after the scene has been released. Scan data is especially important should the scope and direction of the investigation change, as new evidence becomes available.

Gordon personnel are familiar with law enforcement protocols surrounding crime scene integrity. Our scanning equipment and process can successfully meet the legal requirements of the Frye and Daubert tests, as required by the court system. In addition, Gordon’s laser scanning services are recommended by graduates of the Virginia Forensic Science Academy, which is recognized as one of the top crime scene investigation training academies in the world.

3D laser scan data is not someone’s reconstructed interpretation of the scene; it is the scene. Being able to virtually revisit the scene frozen in time exactly as the first responder found it provides public safety officials with a powerful way to visualize and place themselves into the scene.

Recreation of crime scene environments can be established from point cloud data in the form of still imagery or animated fly-throughs. This allows investigators, legal teams, and grand juries to view virtual tours of the scene from the station or courtroom.

4501 Daly Drive. Suite 200 | Chantilly. VA 20151 | 703.263.1900

301 North Mildred Street. Suite 1 | Charles Town. WV 25414 | 304.725.8456

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