Using Datums - About Datums
About Datums
Datums are alignment objects that fully orient a physical part to one of the primary views in the SOLIDWORKS coordinate system. Your digitizing device has its own internal coordinate system also known as the "device coordinate system". Data collected from the part is reported by the digitizing device to RevWorks in device coordinates. Datums instruct RevWorks on how the coordinates gathered from the part must be transformed in order to create the desired part relationship to the SOLIDWORKS model space. Datums orient the part to the SOLIDWORKS origin and either the Front, Top, or Right primary plane. Coordinates that are transformed by the application of a Datum are converted from the device coordinate system to a "part coordinate system." Once a part has been "datumed" it is fully aligned with the SOLIDWORKS model space and screen display.
If you move a part after it has been datumed, you can reset the datum so that newly collected data aligns with previously collected data. Datums are powerful tools for digitizing parts that are too big or complex to reach all features without re-positioning the part or digitizer. Datums also protect you from data loss in case the part you are digitizing, or the digitizer itself, is accidentally moved while you are working. By re-measuring the datum, you can restart data collection without losing registration with data already collected.
Datums that you define are preserved, along with all other related information, when you choose to save an alignment document.
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Warning: If you close the RevWorks toolbar without saving the alignment document, all datum information is discarded. By saving the alignment document you preserve the option of reusing Datum definitions. Depending on the specific characteristics of your digitizer, it may be possible to reactivate a Datum and restart data collection without re-measuring the Datum even after you have completely shut down and later restarted your system as long as the part and digitizer have not been moved. |
RevWorks allows you to orient your part to any of the three primary modeling planes:
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Front Plane
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Top Plane
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Right Plane
RevWorks allows you to create three kinds of datums:
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Three-Point Datum
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Three-Sphere Datum
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Custom Datum
From the RevWorks toolbar, you can create a Datum without opening a SOLIDWORKS part, assembly, or drawing window. You do not have to create a Datum in order to digitize a part with RevWorks. In the absence of an active alignment object, RevWorks presents part data in raw device coordinates.
To better familiarize yourself with Datums, read the following topics:
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