Prior to version 2019 R1, the Primary Datum Plane was referred to as the "Tangent Plane" or "High Point Plane".
PC-DMIS does not currently support the ASME Y14.5-2009 tangent plane modifier.
You can construct a plane that is external to the material (tangent to the peaks or the high points) on a surface. You can then use this feature as a datum in alignments or dimensions. Do not dimension a primary datum plane. That is not its purpose. You should use it only as a datum feature.
To construct a Primary Datum plane:
Open the Construct Plane dialog box (Insert | Feature | Constructed | Plane).
From the Method list, select the Primary Datum option.
From the Feature list, select the input features from one of these options:
Three or more features (you may use any feature type).
Any single feature Set. For information on feature sets, see "Constructing a Set of Features".
Any Plane feature.
Any scan.
Select a math type from the first list in the Math Type area. The available options are:
CONSTRAINED_L1
CONSTRAINED_L2
CONSTRAINED_MINMAX
For information on these math types, see the "Primary Datum Plane Math Types" topic in this documentation.
Select either BF (Best Fit) or BFRE. (Best Fit Re-Compensate) from the second list in the Math type area.
For information on Best Fit planes, see "Constructing a Best Fit or Best Fit Recompensate Plane".
From the Display area, select how you want PC-DMIS to display the constructed plane. For details, see the "Using the Display Area" topic in this documentation.
If you want to change the feature theoretical values, select the Feature theoreticals check box and type in the values. For details, see the "Specifying Feature Theoreticals" topic in the PC-DMIS Core documentation.
Click the Create button.
After you click the Create button, PC-DMIS performs these steps to construct the Primary Datum Plane:
First, PC-DMIS constructs a Best Fit plane from the input features according to the math type.
Next, PC-DMIS rotates to the Best Fit plane.
Then, PC-DMIS finds the optimal primary datum plane from the highest points.
The Edit window command line for this option reads:
CONSTR/PLANE,PRIMARY DATUM,feat_1, feat_2, feat_3,…
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