Diff Pair necking / variable trace width

[GadgetWusky]

I need to route five differential pairs out of a BGA chip.

In the example image above, I've got this diffpair that I need to route into two tight BGA pads. Due to manufacturing clearance requirements, I need to neck the highlighted part of this trace from the diffpair defined width to a custom width for this one single segment only. I tried a few methods of routing narrower traces from the fanout point into the BGA pads and then connect the diffpair to the hanging traces, but the software seems to not allow this unless you trick it into doing it. When I routed the diffpair from the other end over to the BGA fanout, when I make the connection, it changes the already placed traces to the diffpair width, modifying the already placed traces, incorrectly forcing them into the diffpair defined width. How do I route these diffpairs with variable trace width at the BGA fanout? The only two apparent solutions are route the diffpair as two single ended traces and carefully place all the differential pair spacing manually, or draw copper shapes combined with hanging, disconnected nets. Is there a more proper method available in DipTrace?

[Serg]

You can set Neck Parameters for a Net Class and then assign a different width to a selected segment of the trace.
To do this, follow these steps:
1. Open Route → Net Classes, select the desired differential pair class from the list, go to Neck Parameters, and set the Trace Width.
2. On the differential pair, select the trace segment, and in the Properties panel (on the left), choose Neck for the Segment Width option.

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[GadgetWusky]

Thank you for the info.