Referring now to FIG. 5, the region move/layer swap processes invoked in steps 43 and 45 of FIG. 3 are illustrated in accordance with an example embodiment that is used for both region moving and layer swapping. First the user selects the “from” and “to” layers to swap (step 60) and the layers or region on the layers are swapped (step 61). New signal trace widths are computed or are adjusted based on a user-defined impedance definition for the signal trace layer, saved and displayed according to the specified characteristic impedance(s) for the traces bearing critical signals (step 62). An inter-feature spacing check is performed (step 63) and if any spacing violations occur (decision 64) then the feature spacing is increased (step 65) by moving a feature. Once the inter-feature spacing check is complete (decision 64), signal referencing is checked (step 66) to ensure that the signal traces are proximate to a correct reference plane. If a referencing violation is present (decision 67) then a reference plane solution process is invoked (step 68), otherwise the process returns to decision 44 or decision 46 of FIG. 3.