PCB Enhancements

This release introduces site variables that allow you to configure the extraction of the board outline:

• maxOuterHolesRatio (0.1 by default): specifies the fraction of holes (from the drill file) that can lie outside of the outline.

• contourSizeToleranceRatio (0.15 by default): specifies thresholds for constraints on outline size relative to the bounding box of the board's circuit holes. Contours that are too large are likely to represent a different type of border, for example one that includes a legend. It also specifies a threshold for a constraint on outline size relative to similar contours from other layers. The dimensions of the contour's bounding box must be no more than this fraction greater than the dimensions of the bounding box of the board's circuit holes and the dimensions of similar contours from other layers.

If aPriori fails to extract an outline for your PCB part, the following message appears in the Viewer: aPriori is unable to extract the circuit perimeter.... In this case, consider slightly increasing the value of one or both of these site variables. This loosens the constraints. If aPriori extracts an outline, but the outline is not accurate, consider slightly decreasing the value of one or both of these site variables. This tightens the constraints.

For more information, see the section Site Variables for PCB Board Outline Extraction in the PCB chapter of the Cost Model Guide.