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[wptabtitle] IMPORTANT NOTE ON OBJECTS IN ACAD[/wptabtitle]
[wptabcontent]IMPORTANT NOTE ON OBJECTS IN ACAD: When using the following methods (EXTRUDE, SWEEPT LOFT, REVOLVE) you can create solids or surfaces. Whether the object is solid or surface is determined by 2 things:
(1) Whether the polyline is open or closed: Open polygons and curves always create surfaces but closed polylines and curves can create either.
(2) Which tab is active at the top of the ACAD workspace (See Figure 1) – If the Solid tab is active, a solid is created; if the Surface tab is active, a surface object is created; if the Home tab is active, by default, a solid is created from closed polylines (this default can be changed once a command is active by entering ‘M’ for Mode at the prompt) – Solids seem to translate into the COE format and import into Cyclone much better than surfaces, which sometimes will not show up in Cyclone at all in the COE format.
[wptabtitle] SET UP THE ACAD MODEL SPACE[/wptabtitle]
[wptabcontent]I. Set up the ACAD Model Space
1. Configure/Open the Cyclone MS and set up the ACAD model space (See the GMV’s “Leica CloudWorx 4.2 and AutoCAD 2012 – Digitizing a Point Cloud in 2D” for more information)
2. Create Layers for each of the 3 slices and the final column object, making the bottom slice’s layer active
3. Adjust the object geometry association variable in CAD -> command line: DELOBJ > adjust to value zero
(NOTE: This number determines whether the original geometry used to create a 3D object – in this case polylines – are retained or deleted when the object is created. This value can range from ‘0’ through ‘-3’, with ‘0’ retaining all geometry and with ‘-3’ deleting all defining geometry. Retaining geometry is recommended for analysis and any possible back-tracking. Search “DELOBJ” in ACAD help for more information)
[wptabtitle] SETUP ACAD MODEL SPACE – CONT.[/wptabtitle]
4. Hide Regions to isolate first feature to be modeled, in this case, the colonnade.
[wptabcontent]Method 1: Slicing Cross Sections and Lofting – Point Clouds may be sliced to view specific sections or profiles to model; these slices are made across the x, y, or z axis based on the current UCS. Slicing large areas is useful when looking to see which features are the most intact/complete across a site. Slicing small areas allows for precise drawing/modeling. In this method, a column will be sliced and the section’s profile (ie: cross sections) will be traced and lofted into solid or surface objects.
In the first example, the column is sliced 3 times on the y-axis. Tracing the slices creates 3 polylines representing the section cuts from the bottom, middle, and top sections of the columns -> These cross sections will then be lofted to one another, forming the modeled column object.[/wptabcontent]
[wptabtitle] USE THE CLOUDWORX SLICE TOOLBAR[/wptabtitle]
[wptabcontent]II. Use the CloudWorx Slice Toolbar to slice the point cloud along the y-axis as the first section cut at the bottom of the column. Slices can be made in several ways. NOTE: a slice must be named in the Cutplane Manager (main Cloudworx toolbar) in order to be saved; if unnamed, it will be deleted once it is deactivated!!!
1. Clip Point to Slice -> uses two parallel planes to define the slice; only those points between the two planes are shown > Command line: CWSLICE or Cloudworx > Clip Point Cloud > Slice > Define Axis > LC in viewport to place 1st and 2nd clipping planes. NOTE: Current Slice can be moved one step (equal to width of the slice) forward (CWSLICEF) or backward (CWSLICEB) along its axis
[wptabtitle] CLIP POINTS TO SECTION[/wptabtitle]
2. Clip Points to Section > uses single plane with only those points on one side of the plane visible > Command line: CWSECTION or Cloudworx > Clip Point Cloud> Section View > LC in viewport to define axis and direction (positive or negative)
[wptabtitle] TRACE AND SNAP TO POINT CLOUD[/wptabtitle]
3. Trace first section cut, snapping directly to point cloud > Top View > Make correct layer current > Zoom in to view points comfortably and refresh point cloud to confirm all points visible (do this periodically, especially when zooming in/out) >Command Line: PL or POLYLINE to trace the profile/outline of the bottom slice of the column
REMEMBER: (1) Enable OSNAP “NODE” to snap to points (2) At command line: type “U” during active polyline command to undo vertices/go back without ending the command (3) At command line: PEDIT allows polyline(s) to be edited, joined, etc. (4) See ACAD Help: Drawing and Editing Polylines for more information
3A. Repeat Steps to create the polylines for the remaining section cuts (note you may create more or less slices as desired – a higher number of slices and/or increased complexity results in a more accurate tracing but also requires a higher and more difficult set of calculations to loft/join the separate sections; when too complex, the lofting command may fail to calculate the final object as desired) > Confirm each section is made of only one polyline (use PEDIT -> JOIN and PEDIT -> CLOSE to join and close multiple polylines)
[wptabtitle] 3D MODELING MAIN TOOLBAR[/wptabtitle] [wptabcontent]III. 3D Modeling main toolbar > EXTRUDE tab pulls down to LOFT (see figure 4) or at command line: LOFT > Select cross sections in the order they are to be lofted to one another (here from bottom to top) > ENTER after selection > ENTER a 2nd time to accept “Cross Sections Only”
[wptabtitle] RETURN TO ORIGINAL COORDINATES AND EXPORT[/wptabtitle] [wptabcontent]IV. Return to Original Coordinates and export > If you have altered the Coordinate System, return it to the World Coordinate System that matches the original scan world coordinates (See the section: ‘Setting up a Model Space in AutoCAD: Using User-defined coordinate systems’ and Figure 4 for more information) > Modeled object can now be edited or exported as desired > Select objects > File > Export[/wptabcontent]
[wptabtitle] TIPS FOR LOFTING[/wptabtitle] [wptabcontent]TIPS for lofting: Attempting to loft more than 2 complex cross sections, such as highly detailed tracing, may freeze the program or take large amounts of time. If this happens, try lofting 2 polylines at a time to create separate objects and then grouping or converting these separate objects into a single surface or solid object as needed. Retaining the original geometry (ie: the polylines through DELOBJ) and using layers is essential to dividing the lofting command into manageable pieces; to join multiple objects -> NOTE: although multiple objects can be joined together into a single object with the UNION command, objects that have been united do not seem to translate into COE files well; if you have used the UNION command and find importing the COE file into Cyclone is slow or unsuccessful, try the original objects, pre-UNION (this is another case in which retaining your original geometry is very helpful).
[wptabtitle] EXAMPLES OF LOFTING[/wptabtitle] [wptabcontent]