High-Definition (3D) Laser Scanning William H. Gordon Associates, Inc. www.whga.com
WHAT IS 3D LASER SCANNING? Simply stated, a three dimensional (3D) laser scan (also referred to as a High-Definition scan or point cloud)William H. Gordon Associates, Inc. (Gordon) is recognized as a leading provider of professional consulting services is like an image from a digital camera, except that each and every pixel can be established in a real world 3Dto public and private sector clients in the Metropolitan Washington, DC region. Founded in Northern Virginia in 1976, coordinate system. As compared to traditional surveying methods that field identify individual specific points,Gordon has assembled civil engineers, land planners, landscape architects, surveyors, and security/law enforcement 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 orprofessionals located within a regional network of offices to provide comprehensive, multi-disciplined services to expand.address the needs of government and business. 3D Laser Scanning is utilized to accurately capture and store “as-built” or “existing” information for areas ranging TOP20 WA S H I N G T O N , D C 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 ENGINEERING FIRM 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. CAPABILITIES 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 toSite Consulting Services Survey & Mapping Services customize deliverables to meet the clients’ needs without numerous site re-visits.• Civil Engineering • Topographic Surveys• Landscape Architecture • High-Definition Laser Scanning Benefits• Site Security Consulting • Property Mapping Surveys • Gordon can accurately capture and document a building’s• Sustainable Planning/Design • Construction Layout interior or exterior to facilitate the architectural design process• Land Planning • QA/QC Surveys for building construction or renovation. The scan data provides an alternative to existing documents that may prove incomplete• Recreational Facility Planning/Design • GIS/Database Development 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 “Gordon’s mission is to provide value-added professional consulting services associated with mass that may have significant project considerations. the development and stewardship of land and/or facilities.” • 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. Gordon performed 3D Laser Scanning Services at the National 4501 Daly Dr., Suite 200 301 North Mildred St., Suite 1A Gallery of Art in 2007. Chantily, VA 20151 Charles Town, WV 25414
CONTRUCTION MONITORINGConstruction may include activities, such as surface grading, bank/slope construction, stockpile/materialquantities, and QA/QC requirements. High Definition Surveys utilizing Gordon’s 3D laser scanner achieve precisemeasurements in a fraction of the time conventional surveys require. Gordon’s High Definition Laser Scanningcovers 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. Stockpile Monitoring Digital Terrain Model 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, Point Cloud and Photo and the volume can be calculated in the field once all the data is acquired. 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. Earthworks Gordon is able to quickly and accurately scan large areas of excavation to monitor soil volumes, such as the dam site shown here.
TOPOGRAPHIC SURVEYS Project: Meyer Elementary SchoolThe use of a laser scanner for typical topographic surveys is becoming more common place with the evolution Gordon’s surveyors performed HDS of thisof fast point cloud data collection, 360° field of views and scripting. The scanner can be programmed to scan former elementary school grounds as adifferent parts of the site and point space at each setup using scripts, thus permitting the instrument to work part of a repurposing and planning projecthands-free. Gordon crews utilizing conventional survey equipment, such as robotic total stations, are able for the DC Office of Property Management.to supplement the survey with data such as invert elevations. As a result, HDS has become cost effective in The points from the scanner point cloudthe preparation of topographic and ALTA/ACSM Land Title Surveys. Additionally, the value-added benefit of can be cleaned of unnecessary noise andcompiling more data than that of conventional surveying reduces the need for future site visits as the project’s augmented with points from a conventionalscope evolves. survey to create a 3D surface model and a 2D topographic map, as shown here. Project: National Gallery of Art 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.
ARCHITECTURALThe capture of infrastructure on existing buildings for architectural design purposes is greatly enhanced throughthe use of laser scanning. The scanner’s ability to capture data points on surfaces that are otherwise hardto reach or in unsafe locations is invaluable, especially for structures with complex geometry. Most buildingfeatures are vertical or directly overhead, which provide the line-of-sight and angles conducive for a scanner’sbeam. The fact that many buildings may be occupied during survey operations is not problematic since a laserscanner’s dense data capture enables geometry to be complied even when people move through the scanner’sfield-of-view. Exterior Renovation Interior Applications The client needed a cost effective way to This two story atrium at the lobby of this as-built the exposed face of an existing building would have been difficult to as- building being completely remodeled. The built if not for high-definition scanning. building exterior was redesigned to be fitted The captured data was used to create and with a new glass curtain wall. The remote render a 3D model. Three-dimensional measuring capabilities of HDS is extremely models of a building such as this one can cost-effective for most architectural client provide an accurate base for the creation needs. Gordon surveyors saved the client of a Building Information Model (BIM). 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 Concrete Floor As-Built As a precaution prior to construction of The floor of this new building in downtown an adjacent high rise building, clients may Washington DC was constructed with desire to accurately map elements of the an enormous amount of sag. Gordon’s existing building. Gordon’s surveyors surveyors are able to capture all the performed a HDS of this historical house imperfections for structures such as this to capture existing conditions in the event one, which can then compiled into a surface construction activities caused structural mesh of each floor. A grid of elevations damage or marred the exterior of the at five foot intervals was created for the historical home dating back to the 1800s. 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.
MECHANICAL & INDUSTRIALThe need for fast and precise measurements and industrial applications is critical. Whether managing existingspace, positioning pipes, establishing as-built dimensions or planning new additions, a 3D laser scan provides atimely, permanent record, critical decisions, and panoramic imagery. Typical facilities that benefit from the use of3D laser scanning include chemical plants, power stations, water works, gas works, factories, and other industrialfacilities that may have “clean conditions” rooms. 10 Megapixel Image & Point Cloud Wire Frame Gordon’s high definition 3D laser scanner has A 3D model can be exported as a wire a built in 10 mega pixel camera to capture frame mesh to AutoCAD, Microstation or 360° panoramic images. The images can other design software. Additionally, the be draped over the scanned point cloud to as-built wire frame can be imported into create realistic 3D ortho imagery and .avi facility management information systems format “fly-throughs”. Point clouds are also and other BIM applications. applicable for providing “true” dimensions, pipe widths, angles between two planes, and plumbness of walls or columns. 3D Modeling Solution Utilizing state of the art modeling software, 3D “as-is” models of existing plant Gordon can create 3D models from systems are utilized in retrofits, revamps, the point cloud for rendering surfaces, interference checking, or clash detection determining distances/volumes, or locating and reverse engineering. The increased and identifying objects. This post data accuracy reduces variances in engineering collection process includes cleaning and construction, helps reduce errors, and unwanted points from the point cloud, eliminates the need for return visits to the segmentation and fitting of the geometric project site. features (e.g., planes, cylinders, cones, spheres).
ROADWAY & BRIDGESHigh Definition Surveying utilizing a 3D laser scanner is a fast and safe way to capture as-built informationneeded for road and bridge design, inspection, and monitoring. The 3D Laser Scanner can be positioned out ofthe flow of traffic, while providing a 360 degree scan of the roadway, intersection, or bridge. The scans arecombined into an accurate 3D model, which is edited to remove scanned vehicles and other “noise” to create theline work and surface model. The scanning technology allows Gordon to employ safe work zones without laneclosures or impacting traffic flow. Road Surface Repairs Intersection Improvements Gordon employed its Scanstation 2 from the A heavily traveled four lane highway is shoulder of Interstate-66 to capture a four reduced to two lanes prior to crossing the lane section of the concrete road surface in bridge over the Shenandoah River from dire need of repair. The data was captured Harpers Ferry, WV. Gordon’s engineers in two days during heavy traffic periods, needed to design improvements to the while closing only the highway shoulder. intersection of the access road into a Point cloud data can be used to create line section of Harpers Ferry National Park work and surface models for a detailed just before the bridge on U.S. Route 340. topographic map of roadway projects Gordon surveyors were able to scan the such as this one. Additionally, the point intersection in one day collecting all road cloud and digital imagery can identify all features including existing striping without damaged areas for engineering design. impeding traffic. Tunnel Repairs Bridge Design Gordon obtained detailed point cloud data Gordon’s scanner team performed a of a portion of the Interstate 395 bridge- High Definition Survey of this bridge tunnel in Washington, DC. Point cloud crossing over Interstate 395 in Virginia. data was used to dimension and design Three dimensional models of both bridge replacement granite panels of the bridge- surfaces and understructures were able tunnel facades. to be scanned in one day from just four positions.
FORENSICSMost forensic professionals agree that the single most valuable benefit gained from the technology is the abilityfor 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 especiallyimportant 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 scanningequipment and process can successfully meet the legal requirements of the Frye and Daubert tests, as requiredby the court system. In addition, Gordon’s laser scanning services are recommended by graduates of the VirginiaForensic Science Academy, which is recognized as one of the top crime scene investigation training academiesin the world. Crime Scene Preservation 3D Model from Point Cloud 3D laser scan data is not someone’s The data can be modeled into a 3D reconstructed interpretation of the rendering and exported to other software scene; it is the scene. Being able to for additional animation programs. 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. Point of View Imagry and Animation 3D Model - Point Cloud Overlay Recreation of crime scene environments The 3D model helps enhance the visual can be established from point cloud data effects of the 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 | 304.725.8456w i l l i a m h . g o r d o n a s s o c i a t e s , i n c .