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Position constrains how far a hole’s axis may stray from its true position on the CAD model. In ASME Y14.5 the position tolerance is a diametral zone: a cylinder, centered on the true position, that the axis must stay inside. Voyager evaluates that zone for a scanned cylinder against the matching cylinder on the nominal CAD, in a datum reference frame. Position is in the Toolbar in Dimensioning Mode. Position is a location control, not a form control. Cylindricity asks whether the hole is round and straight. Position asks whether that hole is in the right place relative to the datums and the CAD. The tolerance is always a diameter. The panel labels it Tolerance ⌀.

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What you need first

  • A Feature Set that includes the hole as a cylinder.
  • A nominal .STEP file that has finished processing. See Nominal CAD Import.
  • Datums that can locate the hole. A Frame for Position needs a primary datum. Secondary and tertiary are optional. See Datum Definition.
  • An Alignment when you want Voyager to match the CAD cylinder for you. Without an alignment you pick the CAD cylinder yourself.

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Workflow

1

Select Position

Choose Position from the Toolbar, or right-click the scan cylinder and choose Add position control….
2

Select the scan and the CAD

Pick the volume to measure and the nominal CAD. CAD that is still processing, or that failed, is listed but cannot be selected.
3

Pick the two cylinders

Select the Scan cylinder, then the CAD cylinder whose axis is the true position. If the scan is aligned, Voyager marks a lined-up CAD cylinder as matched. If nothing lines up, click the CAD cylinder in the CAD view.
4

Select the datums

Pick the datums that constrain the position, primary first. Click a datum callout or choose one for each rank. A linked frame fills the other side when the scan and CAD are aligned and the datums are linked.
5

Set the tolerance and submit

Enter Tolerance ⌀ in millimeters and submit. The result is a callout on the hole. Drag the leader to place it.

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Reading the result

The callout reports the position of the scanned axis against the true position, and whether that deviation is inside the diametral zone. Measured in names the Frame. When the frame can sit in more than one place — datum shift — Frame steps through the candidates. Open freedoms lists the degrees of freedom the datums did not stop. None means the frame fully locates the hole. The tolerance can be edited after the control exists. The pass or fail state updates without a new extraction.