Use RPS Alignment
This section introduces how to use RPS Alignment.
To use RPS Alignment, perform the following operations:
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You can open the RPS Alignment dialog box in either of the following ways and add features to use:
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In the upper-part ribbon of the Configuration interface, select . In the pop-up dialog box, click + next to Features in use and add features as needed.
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You can also hold the Ctrl key and click to select multiple features in the left-side resource tree of the current part, and then right-click and select .
You can view the part’s drawing to identify the RPS features that need to be selected. -
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After you add the features, select measurement items of the added features in the table below Features in use.
You can view the part’s drawing and determine the required measurement items based on the 3-2-1 rule. 
3-2-1 rule
In RPS, the 3-2-1 rule is used to constrain the six degrees of freedom of a part. Specifically, the part has three dimensions in 3D space—x, y, and z—each with two directions (movement and rotation), making a total of six degrees of freedom. The 3-2-1 rule constrains the part using the following reference points:
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Three reference points forming a plane constrain the part’s movement along the z-axis and its rotation around the x-axis and y-axis.
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Two reference points forming a line constrain the part’s movement along the y-axis and its rotation around the z-axis.
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One reference point constrains the part’s movement along the x-axis.
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Select Auto-recalculate and click OK.
Since there is no measurement data at this point, you do not need to click Calculate. After you select Auto-recalculate, the software will automatically recalculate once all the measurement data for the selected features is obtained. How to determine whether the calculation result is valid?
Obtain the measured values for a feature, and then check the deviation values for that feature on the annotation card. If the deviation values are not highlighted in red, it indicates that the alignment is valid.