How to Capture Reality Scott Diaz – kubit USA John Bunn – kubit USA Oliver Bringmann – kubit Germany AC3983-P Reality capture is a major focus for Autodesk for the foreseeable future. This class describes, compares, and demonstrates the latest methods, trends, and workflows for bringing real-world measurements into AutoCAD®. The class includes an analysis as well as live demonstrations of various measurement sensors, including 3D laser scanners, handheld laser meters, total stations, and digital cameras. We will demonstrate AutoCAD workflows as well as look at Project Photofly from Autodesk Labs. Speakers will also discuss the process for bringing the data into AutoCAD and explain how to create real-world models based on this data. Attendees will be able to decide which measurement technology to choose for their next project. LearningObjectives At the end of this class, you will be able to:  Explain how accurate as-built data saves money  Describe existing measurement methods and their advantages and disadvantages  Evaluate and use the data captured inside AutoCAD  Select the most suitable method for my specific project AbouttheSpeaker Scott Diaz: Scott is managing director for kubit USA of Houston, Texas. Scott has worked and trained directly with kubit GmbH of Dresden, Germany, over the past four years and opened the first United States office—with a focus on establishing reseller networks throughout the United States to support kubit CAD-based products for documenting as-builts. He worked previously as marketing and technical sales manager for an Autodesk® software developer in the plant and process industry. Scott has a background in business management and marketing with an MBA from Lamar University. Oliver Bringmann: Oliver is the co-founder and managing director of kubit GmbH in Dresden, Germany. For the past ten years, Oliver has led the kubit team in the development of AutoCAD®-based software for capturing existing conditions. He is an expert in modern surveying technologies, such as 3D laser scanning. His focus is on software technology and pattern recognition. Oliver is a professional computer scientist with a Ph.D. from Dresden University. John Bunn: John works in technical sales and support for kubit USA, located in Houston, Texas. John has spent more than 12 years programming and utilizing AutoCAD and Autodesk products, primarily for use within the oil & gas industry. John now spends much of his time performing training sessions and demonstrations for creating deliverables from point clouds inside of AutoCAD. He is well-versed with the workings and manipulation of point cloud data within AutoCAD, including pattern-recognition, 2D and 3D digitizing, measurements/deviation analysis, etc. Moving forward John has a core focus on being in-tune with multiple industries in order to create more complete software solutions and workflows. How to Capture Reality Introduction–WhatisRealityCapture? In this lecture you will receive an overview about reality capture technologies which help you to bring real world geometry into AutoCAD / Autodesk software. We have limited the class to an overview of today’s four most widely utilized technologies for geometry capture. The information in this class will help you to understand these technologies and will help you to decide which is the most efficient for your projects. Total Station 3D Laser Scanner Hand-held lasers Images / Photogrammetry There are many other methods to capture geometry and real world measurements. If in the future you meet a technology which is not covered in this class you will at least have the knowhow for evaluating the technology by yourself based on the parameters outlined in this class. Methods to capture non-geometric real world information like noise, air pollution etc. are not part of this class. 2 How to Capture Reality Totalstation/3D‐Disto A total station is an instrument that measures 3D coordinates. It works with a pointing measure beam and captures one 3D point at a time. Horizontal direction HZ V D Vertical direction V Distance D HZ X Y Z Total stations are usually measuring distances with a precision of 2-3mm and the angle directions with a precision between 1” (seconds) and 7” (seconds). Prices for total station are starting at 5k. Thedatacollectionmethods Instrument Point Collection: There are various approaches for collecting data with a total station. The most common method is to save the measured data internally to the instrument on site. Back in the office, the data is transferred to CAD as ASCII points. In a second working step the graphical elements have to been drawn. This is a traditional surveyor’s and entails a bit more post-processing in the office compared to the methods below. Internal CAD Package: Some total station manufacturers provide a small CAD package with their instruments. This makes it possible to see a graphical preview of the measured data and connect the points with lines on site. It usually creates a basic DXF file which can be imported into AutoCAD. In most cases this drawing needs to be finished up with additional work in the office. This approach to data capture allows the surveyor to import the drawing file as already partially complete, along with coded blocks, etc. for aiding the office drafter to complete their work more efficiently. Direct to CAD: The third method is to link the instrument directly with AutoCAD on-site. In this case the final result is nearly finished in the field. No additional export is necessary. There are a few 3rd party packages available which allow for direct connection between the station and various CAD packages, including AutoCAD. This approach to surveying is typically considered the most user friendly for the non surveyor. If a user has a decent understanding of the CAD package, the total station merely plays the role of a “real world mouse” in the field. Instead of a user clicking points for design with their mouse, the total station is used to draw the real world to 3 How to Capture Reality CAD. This is the method demonstrated during the class and you may view a graphical representation of this below. A 3rd party application (kubit TachyCAD) is used to link AutoCAD directly with a total station. Here a Leica 3D-Disto is used. The upper right window shows the “camera view” of the instrument which is used to “shoot” the points. The coordinate of each point is immediately transferred to the AutoCAD command line for further processing. Based on the active command running, AutoCAD begins to design with the coordinates assigned to it from the 3D Disto/total station. Pro’s/Con’softotalstationmeasurement Pros + The user defines exactly the points of interest. + The data come out in real 3D. + The drawings can be completed in the field (optional). Cons - For a high volume of points this technique is time consuming. 4 How to Capture Reality LaserScanner A 3D laser scanner is a device which captures 3d points in high speed. The result of the surveying process is a 3D point cloud which represents the existing conditions of the measured area. The three most common laser scanning methods are listed below. Static/Terrestrial Scanning Mobile Scanning Airborne Scanning In a very short time a 3D laser scanner captures millions of 3D points with a very high density. Example: A typical setting for the FARO Focus 3D, one of the most common terrestrial laser scanners on the market is 50 Million points for a full 360° scan. This scan takes ~1min and gives you in a distance of 20 meters a density of ~ 1cm. This is the scanner demonstrated in the classroom. 5 How to Capture Reality Howdoes3D‐LaserScanningwork? To captures a single 3D coordinate the laser scanner measures for each point the distance, a horizontal angle and a vertical angle. How to Capture Reality HowtointegratepointcloudstoAutoCAD The following Autodesk products already support point clouds:     AutoCAD Revit Navisworks 3D Studio Max (Labs) AutoCAD includes an Attach and Index command for point clouds. The Attach command inserts the point cloud. This is very similar to inserting a raster image or a block reference. AutoCAD will need a point cloud as a PCG or ISD file. Both formats are proprietary Autodesk formats. The Index command creates PCG or ISD files from external file formats. At the moment AutoCAD supports the import of LAS () which is a standard for airborne and mobile scanning data and FWS/FLS (FARO) files. There are third party products (like kubit PointCloud Free Edition) available which provide imports for other formats as well. We expect to see the Autodesk team providing wider support for common laser scanning formats in the future. AutoCAD has also a slider to adapt the display density. An inserted point cloud within AutoCAD is mainly used as reference information. AutoCAD allows snapping to each point of the point cloud which makes basic line work or annotation easy. How to Capture Reality 3D point cloud attached to AutoCAD An annotated point cloud in AutoCAD 8 How to Capture Reality For advanced evaluation of the point cloud there are 3rd party applications like kubit PointCloud, PointSense Plant, Leica Cloudworx, Pointools Model and ScantoBIM available. The Autodesk Labs team also provides additional tools with Shape Extraction for AutoCAD and the Feature Extraction for Civil 3D projects. The idea behind all of these tools is to improve the process to convert a point cloud into a full CAD model or to aid the user in analysis of existing structure conditions, clash information with existing models, etc.. Theprosandconsoflaserscanning The biggest advantage of laser scanning is the combination of speed, precision and density. A point cloud gives you a realistic and measureable “picture” of reality in minutes where traditional methods would need days. It captures everything on-site, so users are able to avoid return trips to the field for missed measurements. Over the last few years the laser scanning market has experienced a dramatic price decrease for laser scanners. Scanners are now starting at 40K..There are also rental options available which helps to minimize the investment to start with this technology. Many firms also specialize in laser scanning service providing for companies that do not need to make a full investment into the technology. The technology’s biggest advantage of speed, precision and density is also the major challenge. The tremendous amount of data collected from the device can make processing and evaluation time extremely time consuming. Time saved in the field is often transferred to more time in postprocessing in the office. As software becomes more powerful and more specialized for user’s specific workflows, the amount of post-processing time in the office will begin to decrease. This process has already improved dramatically over the past couple of years. Sourcesforfurtherinformation SPAR Point Group, Industry information, technology background: www.sparpointgroup.com User forum: www.laserscanning.org.uk/forum 9 How to Capture Reality Hand‐heldlasers The handheld laser is the electronic version of a tape measure. A single laser beam is sent out from the device, reflects off of the surface of contact and returns the beam to the device resulting in an accurate distance measurement. This distance is reported to the device’s interface. This technology is considered entry level for reality capture in terms of both complexity and cost. The more useful/flexible handheld laser devices range from $400-$800. ClassicalApplication: Hand held lasers typically include the ability to take distances, perform area calculations as well as specific triangulation calculations within the device interface. The most popular use of the handheld laser is performing 2D layout/plan creation from existing conditions. The user walks the room measuring from one length of wall to the next. Users must keep in mind that the device is only capable of taking distances and not angles. Non-linear and non-perpendicular measurements, arcs or complex shapes are difficult to capture and typically require triangulation calculations. This means more measurements to calculate a single point. Triangulations are also making certain assumptions which can cause inaccuracies. Pen/PaperMethod: The user measures each distance from one end of a wall to the next. Doors, windows and other room information are measured similarly. Each distance is labeled on a piece of paper and a rough sketch is drawn in the field. This sketch is then taken back to the office where the information is drawn as a floorplan in a CAD package or used as a basis to create a 3D model. 10 How to Capture Reality This method can be efficient for the experienced surveyor but still leaves open the need to complete the full design back in the office. The method also carries a higher risk of forgetting a measurement in the field. BluetoothtoDatabase: Some handheld laser devices integrate Bluetooth technology. This allows data captured with the device to be transferred immediately to an external interface. One workflow includes the surveyor sending needed measurements to a pre-configured database. These distances are then used to create plan drawings in the office. This method provides better organization of captured measurements but still runs the risk of forgetting a piece of the design in the field. Manufacturers providing Bluetooth integration include Leica (D8, D330i), HILTI and BOSCH. These manufacturers tend to include a basic integration to a PC. There are also a number of 3rd party applications that allow for this workflow. MeasuretoCADviaBluetooth: This final method allows the handheld laser to be connected directly to a CAD interface for simultaneous “measure to design” workflows. Some devices come equipped with packages which provide this basic connection. The more robust applications for architectural design come from a variety of 3rd party developers. Users can walk the room, send measurements to the CAD interface and finish the command with a floorplan drawn to CAD. Most of these program include commands for doors, windows, blocks, reflected ceiling plans, stairs and more to work seamlessly with the handheld laser. This allows for a user friendly and efficient method of creating plans drawings while onsite. Measurements can be verified and the final drawing can be checked for any missing items before the user leaves the site. This method is demonstrated during the class. 11 How to Capture Reality HandheldlaserProsandCons Pros     Low Cost: Highest quality devices range from $400-$800 Easy to use and low learning curve for non surveyors Simple integration with external programs pending Bluetooth integration (AutoCAD database, etc. Drawings can be completed and verified in the field Cons  Distance only (No angle measurements)  Triangulations required for non-perpendicular work o Non 90 degree walls, arc, block locations, etc.  Not optimal device for complex geometry capture  Not optimal for 3D data capture 12 How to Capture Reality Photogrammetry 2DPhotogrammetry(Rectification) The most basic approach for capturing reality from digital photos is the process of image rectification. Although simple and powerful, it is only suitable for taking measurements in a single plane – and thus “not really 3D.” Image rectification is suitable for many applications (façade plans, archeology). Unrectified (left) and rectified (right) photo ready to take measurements Input: a) Single image, b) known control points or coordinates (min. 4 typically collected with a total station or 3D measurement device) or c) known reference measurements from the object in the field (straight lines) + distance measurement Output: Rectified, true-to-scale image Pros: simple, easy-to-use Cons: restricted to a single plane of measurement 13 How to Capture Reality 3DPhotogrammetry Photo overlay in AutoCAD Sometimes referred to as Stereophotogrammetry, it is the process of measuring 3D objects using two or more photos with known camera position, orientation and internal parameters (focal length, lens distortion etc.). The camera parameters are being calculated from a set of corresponding feature points / control points visible in two or more photos. The feature points and the correspondences can either be found automatically (Photofly & Co.) or defined manually, which usually yields a higher accuracy. The fully automatic approach is computationally expensive. The “infinite” computing power of cloud computing services has just made this possible. The bye-product of automatically detected and matched feature points is a 3D point cloud or a 3D surface model (mesh) without modeling anything by hand. Theclassicalway… …uses 2 or more photos with a few measured control points. The feature points and correspondences can also be found automatically using unique markers together with special software which is able to detect them. Input: 2+ images, measured feature points, correspondences 14 How to Capture Reality Output: oriented images which are ready for taking 3D measurements using forward intersection of projection rays. (The point in image 1 is the same point in image 2 allowing definition of a 3D point in space through a triangulated calculation) Pros: high precision, computationally inexpensive, no restriction on the type of objects plotted Cons: measurements must be done by hand and usually provide 3D points only. ThePhotoflyway… …uses many photos combined with the power of cloud computing (usually) to detect feature points and correspondences. In the end, oriented images are created as well as a 3D model (point cloud or surface mesh) of the scene. The quality (accuracy and completeness) depends on the structure of the scene and the quality of photos provided. Input: Large number of images depending on the scene/object being measured. Output: oriented images, feature point clouds, 3D models (meshes) Pros: Easy to use, fast process from field to finished result Cons: not applicable for objects with repeating textures (e.g. brick walls) and specularities (e.g. glass surfaces), accuracy depends on many factors; Data must be uploaded to web servers. From a set of Photos to a 3D model in a few minutes (123D Catch) SoftwareandServices The following selection is not meant to be an overview of all Photogrammetry software packages. It focuses mostly on cloud-based fully-automatic services. Autodesk 123D Catch fka Photoscene Editor aka Project Photofly www.123dapp.com/catch acute3d – the power behind 123D Catch www.acute3d.com ARC 3D – a Photofly-like web service; KU Leuven, Belgium www.arc3d.be 15 How to Capture Reality Bundler Tools – a tool chain of open-source SW, non-cloud-based; topoi, FU/HU Berlin, Germany server.topoi.hu-berlin.de/groups/bundlertools/ LinkstootherAUclasses “It’s a Snap! Take a Photograph and Create a 3D Model” AC4056 (http://au.autodesk.com/?nd=event_class&session_id=9133&jid=1748713) “It’s a Snap! Take a Photograph and Create a 3D Model (Hands-on lab)” AC4058-L (http://au.autodesk.com/?nd=event_class&session_id=9155&jid=1748713) Howtochoosetherightrealitycapturetechnologyformyproject? There is no such thing as THE ultimate technology. Each technology has specific advantages. The key is taking the advantages from each technology to your specific project: Combine them! In many projects a mix of the technologies guides you to the highest level of efficiency. Here are some areas to keep in mind.      Don’t “boil the ocean.” What is the amount of information (e.g. number of 3d coordinates) which I need to represent my final result? Measuring a perpendicular four wall room with a laser scanner to get four corner coordinates will of course work, but in this case a Hand-held laser is the better decision. Do I know which information is needed at the beginning of my on-site work? Is there a possibility I will need more details later in my project? In this case a technology like laser scanning which captures everything makes a good choice because it avoids expensive revisits to the field. Is there a need to limit my time on-site? E.g. someone has to close an area during the on-site work so a quick on-site time is important and afterwards I can work longer in the office. Compare always the complete process from field to finish. Think from the end. Always have a focus on the full workflow into AutoCAD. Avoid “digital gaps”. 16