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Features List 13
From CAD User AEC Magazine Vol 15 No 05 - MAY 2002
David Chadwick takes a closer look at Cyra's CloudWorx, a plug-in for AutoCAD and Microstation that enables them to handle the huge point cloud data files produced by 3D laser scanning.
Cyra has recently made available a plug-in module for AutoCAD and Microstation that enables cloud point data to be manipulated within each application. CloudWorx takes data from Cyra's Cyclone 3D scanning software and displays it in the native CAD environment. data.
A Cyclone point cloud is an accurate 3D representation of a structure, captured using the Cyrax 3D laser scanner, and can be used as the starting point for designs and other CAD activities. In combination with the CAD design and drafting tools, it can be used to generate accurate 2D and 3D plan and elevation drawings, visual interference checking of conceptual design.
Cyrax laser scanners, portable scanning systems, work to an accuracy of just 6mm in 50 metres by bouncing green laser beams off the surface of the structure and timing the length of time between the emission and reception of each pulse. The scanners have 40 x 40 degree fields of view, and are capable of interpreting the density of the surface of the structure to enhance the accuracy of the data. A composite view of the structure is obtained by placing the scanner at a number of locations around it, and correlating the data obtained at each location, assisted by targets placed at strategic points on the structure.
Point clouds, generated from the Cyrax scanner, which operates
at 1000 points/second , are large data files, comprising millions
of points of data, each representing the x.y.z co-ordinate of one
point of the structure.
CloudWorx provides CAD applications with the ability to utilise cloud point data, and is supplied as a plug-in - a separate drop down menu being made available in the main AutoCAD and Microstation tool bars. The data from Cyclone is made available to the applications in read-only format to preserve the integrity of the data - it can't be subsequently modified or deleted.
The principal advantage of using CloudWorx with AutoCAD, Microstation, or any other CAD application, is that such software would be incapable of being used to create files of such enormity, with millions of points, and that CAD software, using the rendering engine of Cyclone, can be used to display, slice and otherwise manipulate the points more effectively.
Available only for networked systems, and in AutoCAD 2000 and beyond - the licensing procedure uses the serial number of the network card and the PCIP address to assign the software to a particular user - CloudWorx is simple to load and run. Point clouds are similarly easy to load. Typing POINTCLOUD into the AutoCAD dialogue box brings up the Point Cloud Creation dialogue box. Browse until the required data is located, and then define the units and co-ordinates being used in AutoCAD. Cloud point data is stored in metres, and the data has to be converted to the scale of the AutoCAD drawing. Clicking on the point cloud ModelSpace returns the user to the Point Cloud Creation dialogue.
Once the data has been loaded, it is available for simple viewing - zoom, pan, rotate, snap to points - or to orbit the cloud using ordinary AutoCAD commands. CloudWorx simplifies the graphic representation to enable the vast files to respond quicker to the commands. Boundaries can be set, and groups of points shown or hidden to improve the visualisation of the model.
Pointcloudhide hides groups of data, specified by the user, from
view, making it easier for work to be carried out on those points
that are still visible. Very simple to do - rectangles are created,
and the user specifies whether he wishes to view points inside,
or outside the rectangle.
A valuable command that is often used to analyse the thickness of structures, or to display the true shape of an irregular column, is the Slice command.
This allows users to define planes across an image, and clip points outside the planes so that a cross-section of the cloud can be viewed - simulating a 2D representation of an area. The 'slice' can then be moved successively in each direction away from the original slice for further analysis. (Slices can only be made in one plane at a time). These slices are invaluable tools to reveal plan-views, cross sections of buildings, plants, etc. - and to enable a designer/engineer derive 2D drawings by simply tracing the 2D views. Zooming and snap-to-point features greatly facilitate this activity in terms of speed and accuracy.
Querypoint is another useful command from the short CloudWorx pull down menu. It enables users to identify individual points within the cloud - or to use AutoCAD's measuring facilities to measure distances between points.
Importing and exporting objects into AutoCAD is performed not through CloudWorx, but through an additional feature, the COE import/export tool. CloudWorx loads the point cloud data, but the COE tools allow Cyclone modelled objects into AutoCAD, and to export AutoCAD modelled objects back into Cyclone. Objects can be exported either with the point cloud data for reference, or without.
Cyclone 3.1 is the more robust (and more expensive) standalanone application from Cyra Technologies. In this application one can register (stitch together) several point clouds and using Cyclone's "region grow" command semi automatically turn point data into CAD models.
Models can then be converted to solids or surface objects in AutoCAD by snapping onto objects and importing solid objects - or, indeed, catalogue objects or other 3D real life data.
Cyclone, the original and widely used point cloud creation and modelling software from Cyra incorporates this ability within itself, enabling surface objects within the point cloud to be calculated, making 3D objects out them - e.g. pipes and flanges in a complex oil refinery, once recognised using the viewer, can be converted to 3D pipe and flange objects from the software's object library.
Shrink Wrapping is a term often used in conjunction with point clouds. It means that the point cloud data is converted to a mesh, suitable for rendering using the application. Meshes are either simple ones, based on a frame grab of the scanner mesh, or sophisticated TIN meshes - continuous related mesh data, used regularly by surveyors in GIS applications. TIN meshes are capable of being used for more advanced rendering, contour lining or volume calculations.
Delaware River Joint Toll Bridge
CloudWorx was used recently by Washington Group Infrastructure Services, who conducted a survey for the Delaware River Joint Toll Bridge Commission. The Commission wished to upgrade toll booth plaza for electronic toll collection. The orginal plans dated back to the 1950's however, and were inaccurate. In fact, measuring and defining the current structure was a major part of the reconstruction project, and, because WGI LSS (WGI Laser Scanning Services) were able to shave so much of the cost of that part of the project by using Cyra's 2500 3D laser scanners, Cyclone and CloudWorx, their overall bid was 33% less costly compared to the other potential contractors - and they were awarded the contract.
The existing booths were scanned from the back of aerial lift trucks, so that they could see over the tops of vehicles using the booths, and were completed in a single day per booth -against three days by their competitors. The data was enhanced using a technique called Intensity Mapping -and digital photography, providing small details such as outlet covers and access panels. Once the data was captured, it was used as a design reference to create 2D and 3D geometry, using CloudWorx to merge point data with CAD models. CU
CloudWorx, available from Leica and Cyra dealers worldwide,costs
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