Make the most of Scanned Data in AutoCAD 2013 Tilo Pfliegner – kubit Matthias Koksch – kubit AC4440 Get a jump start on your AutoCAD designs by taking advantage of existing 3D point cloud data. We will take scanning to the third dimension as we explore the power of point clouds. Learn the latest methods, trends, and workflows for bringing real-world measurements into AutoCAD software. Understand the laser scanning process and how the real world gets into AutoCAD. Explore the AutoCAD point cloud tools for attaching and managing point cloud files. Finally, expect a close analysis as well as live demonstrations of design methods for going from real-world data to native AutoCAD 2D and 3D design deliverables as we maximize the power of point clouds. Learning Objectives At the end of this class, you will be able to: Operate a 3D laser scanner and describe the general workflow in the field Bring the real world to your AutoCAD environment with point clouds and laser scanning Evaluate and design with point clouds in AutoCAD Select the most suitable field-to-design methods for your specific project About the Speakers Tilo Pfliegner is a professional Software Engineer at kubit GmbH in Dresden, Germany. For more than 10 years Tilo has been responsible for the development of a variety of AutoCAD-based software for surveying and as-built documentation. Currently his focus is on research & development of modern workflows for 3D laser scanning. Tilo holds a Computer Science degree from Dresden University, where he specialized in Computer Vision techniques. When he isn’t coding, you’ll find him cycling or climbing Dresden’s beautiful surrounding landscapes. [email protected]Matthias Koksch is co-founder and managing director of kubit GmbH in Dresden, Germany. For the past ten years, Matthias has led the kubit team in the development of AutoCAD based software for capturing
Transcript
Make the most of Scanned Data in AutoCAD 2013Tilo Pfliegner – kubit Matthias Koksch – kubit
AC4440
Get a jump start on your AutoCAD designs by taking advantage of existing 3D point cloud data. We will take scanning to the third dimension as we explore the power of point clouds. Learn the latest methods, trends, and workflows for bringing real-world measurements into AutoCAD software. Understand the laser scanning process and how the real world gets into AutoCAD. Explore the AutoCAD point cloud tools for attaching and managing point cloud files. Finally, expect a close analysis as well as live demonstrations of design methods for going from real-world data to native AutoCAD 2D and 3D design deliverables as we maximize the power of point clouds.
Learning ObjectivesAt the end of this class, you will be able to:
Operate a 3D laser scanner and describe the general workflow in the field
Bring the real world to your AutoCAD environment with point clouds and laser scanning
Evaluate and design with point clouds in AutoCAD
Select the most suitable field-to-design methods for your specific project
About the SpeakersTilo Pfliegner is a professional Software Engineer at kubit GmbH in Dresden, Germany. For more than 10 years Tilo has been responsible for the development of a variety of AutoCAD-based software for surveying and as-built documentation. Currently his focus is on research & development of modern workflows for 3D laser scanning. Tilo holds a Computer Science degree from Dresden University, where he specialized in Computer Vision techniques. When he isn’t coding, you’ll find him cycling or climbing Dresden’s beautiful surrounding [email protected]
Matthias Koksch is co-founder and managing director of kubit GmbH in Dresden, Germany. For the past ten years, Matthias has led the kubit team in the development of AutoCAD based software for capturing existing conditions. As an expert in modern surveying technologies such as 3D laser scanning, his focus is on educating and standardizing these new technologies for the masses. Matthias is a professional surveyor with a degree from Dresden [email protected]
How to get a 3D Point Cloud?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.
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.
The three most common laser scanning methods are listed below.
Figure 1 To capture a single 3D coordinate the laser scanner measures for each point the distance, a horizontal angle and a vertical angle.
Make the most of Scanned Data in AutoCAD 2013
RegistrationDuring a complete project the laser scanner is usually placed on multiple positions to get a complete documentation from all sites. Every single scan creates a single 3D point cloud.
In a next step each individual point cloud is registered to each other. As a result of the registration process one point cloud data set within one coordinate system is created. This registered point cloud is now ready to use for evaluating in AutoCAD.
6 individual scans Registered Point Cloud
To register the individual scans together identical objects in each scan are needed. Depending on the covered object and the needed precision this is usually done by placed targets. The targets need to be placed on site before the scanning process starts so that they are part of the point cloud.
An alternative to targets is to use natural objects (planes, corners, etc.) within the scan as reference objects for the registration process.
Other Reality Capture TechniquesThe first part dealt with terrestrial laser scanning (TLS). Other laser scanning techniques commercially used are Mobile Scanning and Airborne Lidar. The main difference to TLS is that the capturing device is not on a fixed position while measuring but is mounted atop (or beneath in case of Airborne) a moving vehicle (car, plane, boat, …). Both techniques are cost-intensive but should be considered if there’s a need to capture large areas.
Additionally there are some other kinds of 3D data capturing techniques which are
more affordable than laser scanners „emerging technologies" suitable for a relatively broad range of applications
Make the most of Scanned Data in AutoCAD 2013
We pick out two out of many: Multi-view Photogrammetry and Range cameras.
Multi-view PhotogrammetryMulti-view Photogrammetry is based on the inversion of the image formation process. The working principle is:
Take photos from all directions (possibly aided by a UAV) Extract feature points in all photos Match feature points between all photos Orient the photos in space Reconstruct sparse point cloud (based on feature points) (Densify point cloud) (optional)
The result is a textured 3D mesh or a dense point cloud. The accuracy of the resulting point cloud depends largely on the captured object’s size and surface texture. It is also sensitive to repetitive textures and specularities.
It is most suitable for relatively small objects.
All you need to start is a digital camera and one of the free tools (and web-services) available for Multi-view photogrammetry:
Range camerasRange cameras are cheap (below $200), lightweight (mountable onto lightweight UAV's such as Quad-/Octocopters) and provide 3D data in real-time. However range cameras lack the existence of software tools ready for productive use. Due to the short range (<5 Meters) and the limited Field-of-View they are best suited to capture smaller scenes, although newer SLAM (simultaneous location and mapping) allow for capturing of larger areas.
Figure 2 Microsoft Kinect (left) and point cloud of the speaker captured with Asus Xtion+SCENECT
1 Cloud based. Photos are uploaded to a server which performs the heavy computations.2 A collection of Open Source tools that runs on Linux.
The working principle is structured light. A light pattern (IR) is projected onto the object which is captured by a dedicated camera sensor (IR). Depth is calculated by analyzing the distortion/deformation of the pattern.
The most prominent representatives are Microsoft Kinect and Asus Xtion.
The Point Cloud in (vanilla) AutoCAD 2013
EvolutionHistory of point clouds in AutoCAD
Mid-1990s Terrestrial Laser Scanners become commercially available
2000+ AutoCAD point cloud applications by 3rd party developers (point clouds as custom entities)
2008 Autodesk licenses the Ambercore point cloud engine (ISD format) to be first included in Civil3D and Map3D
2010 Autodesk releases its own point cloud engine (PCG format), lightweight, high-performance point cloud engine (for AutoCAD 2011) with very limited capabilities
2012 AutoCAD 2013 improves PCG engine in terms of interoperability and visualization capabilities
This preparation of the scan files is generally done by the Pre-processing application available together with the scanner hardware.
Make sure you’ve switched on „Hardware acceleration" (command: 3DCONFIG). This is essential to visualize the point cloud colored and with good performance. If possible, use a certified and recommended graphics card (see here for a full list: http://tinyurl.com/d5fkvjv). If the graphics card is not supported by AutoCAD, you will not be able to switch on Hardware acceleration”.
Switch to a 3D visual style, e.g. “Wireframe” or “Realistic”. In fact any other than 2D wireframe will do. Again this is important for colored and high-performance visualization of the point clouds.
IndexImport the data from the native scanner formats into the Autodesk point cloud format (PCG).
Point clouds (like images) are being inserted based on the current UCS and are referenced in the drawing (like images, Xrefs).
Locking the point cloud will prevent it from being transformed or erased.
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Make the most of Scanned Data in AutoCAD 2013
Do not specify Insertion point, Scale & Rotation on-screen (except if you have a very good reason for that). Do specify the Scale when working in a unit different than the scan unit, which is Meters in most cases. Refer to the following table for scaling factors:
Drawing Unit 1/Meters Scaling factor (if point cloud is in Meters)
DisplayRemember to enable Hardware Acceleration and set a 3D Visual Style (e.g. “Wireframe”).
The following AutoCAD system variables affect the point cloud display:
POINTCLOUDDENSITY [1..100]: Percentage of points to be displayed at a time. 100=number specified by POINTCLOUDPOINTMAX
POINTCLOUDRTDENSITY [1..100]: Percentage of points to be displayed during 3D navigation. POINTCLOUDPOINTMAX [1.5M..10M]: Defines the maximum number of points to be displayed
(if Density=100)
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Make the most of Scanned Data in AutoCAD 2013
Figure 5 Visualizing different POINTCLOUDDENSITY/POINTCLOUDPOINTMAX settings (left: 15/1.5M, right: 100/10M)
So the maximum number of points to be displayed is specified by the formula POINTCLOUDDENSITY*POINTCLOUDPOINTMAX/100. The maximum value that works on your system depends on the graphics card.
Selecting the point cloud will show the contextual ribbon tab where you can access (nearly) all functionality to edit the appearance of point cloud.
Figure 6 Point Cloud Contextual Ribbon Tab
After toggling Intensity display you can apply different color schemes. Color schemes for Intensity allow for identification of details in highly complex point clouds.
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POINTCLOUDDENSITYPOINTCLOUDRTDENSITY
Switch color between RGB and By object
Toggle intensity display
Specify color model & color mapping
Clipping
Bounding Box, useful to identify extents of the point cloud when clipped
Show Xref palette
Make the most of Scanned Data in AutoCAD 2013
You can adjust the mapping using the command POINTCLOUDINTENSITYEDIT (Ribbon: Cloud Analysis Intensity Color Mapping). Intensity minimum and maximum are percentage values (1=100% Intensity).
Figure 7 Color ramps (left) and adjust color mapping dialog (POINTCLOUDINTENSITYEDIT )
ClipCommand: POINTCLOUDCLIP
Ribbon: Point Cloud Clip Create clipping boundary
You can clip a point cloud to reduce it to a certain volume of interest. Clipping can also provide means to get a better visual fidelity as points that are clipped away are not considered regarding the POINTCLOUDPOINTMAX setting.
Clipping is per-point-cloud and always along the z-Axis of the point cloud's coordinate system. More advanced (view- and UCS-based clipping) are being provided by 3rd party tools.
The POINTCLOUDCLIPFRAME system variable specifies if clip frame is displayed/printed or not.
Designa) Access every single cloud point with OSNAP „Node" (Example: pick a point on the ceiling to
extrude geometry up to the ceiling). Be careful when having points in background, they are sometimes snapped. Clip the point cloud to avoid this behavior. Also remember the good old point filters (.xy, .z) and all the other things available with SHIFT+Right Mouse Button in order to creatively use point cloud geometry.
b) Use the point cloud as visual reference (Example: Disable OSNAP “Node” to digitze a floor plan).c) More sophisticated analysis & modeling features are being provided by 3rd party applications.
Rendering & PlottingPoint clouds do not render!
Point clouds are printed & plotted monochrome only!
Simple animations can be done via ANIPATH command.
Useful Tips & Tricks1. Use command 3DORBITCTR to specify center of orbit rotation.2. Use POINTCLOUDDENSITY/POINTCLOUDPOINTMAX system variables to control visual fidelity
of the point cloud.
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Make the most of Scanned Data in AutoCAD 2013
3. Use individual (per scan or group of scans) PCG files to split up the whole project.4. When saving the drawing in AutoCAD 2010 DWG format, the point clouds are going to be
recreated (AutoCAD 2013 version of PCG is incompatible with AutoCAD 2011 and 2012)!5. Create a drawing template with „Wireframe" as default visual style.
TroubleshootingMy point cloud is monochrome only (black/white)?
No true color information, try intensity based coloring Enable 3D visual style + Hardware Acceleration
My point cloud disappears and only appears during 3D navigation?
Your graphics card is not able to handle the total number of points to be displayed as specified by POINTCLOUDPOINTMAX*POINTCLOUDDENSITY/100. Try lowering those values or purchase a better graphics card (http://tinyurl.com/crp389y).
My point cloud looks bad (sparse)?
Try increasing values for POINTCLOUDDENSITY+POINTCLOUDPOINTMAX
The point cloud I’ve created does not load in my colleague’s AutoCAD 2012
See Tips & Tricks. AutoCAD 2013 PCG files need to be recreated (save drawing as AC2010 DWG)
3rd party applicationsAutoCAD 2013 comes already with some basic functionality for 3D Point Clouds. Basically it allows to import (index) and to attach Point Clouds. With the OSNAP Node it is possible to snap to each individual point of the Point Cloud.
AutoCAD also provides an API (Advanced Programming Interface) for Point Clouds. This API allows 3rd party developer to develop applications which provide additional Point Cloud functionality. Features which are provided by 3rd party applications are things like:
- Sectioning/Slicing- Feature Extraction for basic geometry- Adding Intelligence
Good examples for 3rd party applications are the PointCloud/PointSense software from kubit (www.kubit-software.com). Others can be found at the Autodesk Partner Products Catalogue (http://partnerproducts.autodesk.com/catalog/default.asp).
