Polyworks Tech Tip: This Tech Tip demonstrates how to reverse engineer the part using data-to-data objects alignment tool in Polyworks.
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Welcome to another video on tech tips from CMMXYZ. Today in this video, let's discuss how to align data objects using data to data alignment in PolyWorks. This tool is useful when data objects are acquired in multiple device or part positions that are not aligned to each other. This technique is useful for reverse engineering where a physical part is digitized to a scanned data which can be later exported as a CAD model in different file formats. In this example, you can see that a pipe has been scanned multiple times from different positions by creating new scans for each part position. You can also observe that an alignment group is created from individual scans in the preview. Now our objective is to align all the data objects to get a CAD model from the scans. To start the alignment, keep the two scans visible and hide the remaining scans.
Now go to Align, Best-Fit Data Objects and Data to Data Objects. Here, we have two methods. First is align data objects, which is used to align two data objects. And the second is to globally optimize all the aligned data objects, which is the last step in the process.
Having Prealign using points pairs checked, select the data object to align, which is mesh 2, and select the Fixed data object, which is mesh 1. Keeping all the parameters at default value, press Start. Note that the fixed object hasn't moved while aligning. Fixed data objects will be on the left and the data objects to be aligned is displayed on the right view.
Adjust both the views to a similar orientation. After adjusting the orientations, choose the endpoint pairs prealignment method and pick three minimum matching points on both data objects in the same order. However, it is recommended to take four to five points. Matching points are displayed using the same color and same number. Then click on Align to align the data objects. Best-fit is automatically performed after the prealignment. After the two data objects are aligned, close the Best-Fit Data to Data Object log, and unhide the next scan that has to be aligned to the fixed object. Repeat the process for the next scans until all the scans are aligned to the fixed object.
Use space bar or 3D manipulation icon to rotate the display while taking points. To delete the previously picked points, click on the middle wheel on the mouse, or use the undo icon.
In the preview, you can observe that best-fit to data alignment is added in the alignment groups. After the prealignment, again, go to Align, Best-Fit Objects, Data to Data Objects. Now, select the globally optimized alignments method. This option is used to optimize the alignments between all the data objects using surface information. This is basically having one alignment for all the data objects. In Data objects to align, select All and click on Start to globally optimize the scans. You can now see in the preview, a global optimized alignment is added in the alignment groups.
Next, we can select on scanned data, right-click, and export the aligned objects as a polygonal model. Select the required file format here, and saving the scanned data as an STL file to reverse-engineer the part in CAD softwares. This was a video on data to data object alignment. Thank you for watching the video.
