Hard time routing differential pairs

Layout
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People wanted the curved option because sometimes straight would become hidden as they overlapped or lay one on top the other.

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I donā€™t think so. My schematics look quite right. This may be an issue with the router itself.

Sure, makes sense. And both versions (straight and curved) are available and can be selected. Maybe, the curved one can have a little bit more love in the futureā€¦ maybe it could be tweaked to curve to the same side for differential pairs.

Now another thing I am thinkingā€¦ since routing is quite hard on Kicad 6, I am wondering if it is possible to open the kicad_pcb with an older version, letā€™s say Kicad 5.1.12 to have a better behavior while routing. I am not sure Kicad 6 PCB can still be opened with Kicad 5. I will have to install it here to check.

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This is the first version to offer them so feedback may help drive some tweaks.

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The quick answer is no, you canā€™t open KiCad 6 files with KiCad 5 as is. The file format has changed quite a bit to allow for features like the curved traces, so youā€™d have to use an external script to remove new features (or do it by hand).

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Curved tracks are good to have as option. But now there are bugs. For instance, I suddenly got some curved tracks when I was doing some long routes. But now I see no curves with new tracks. I changed some options, so that may be the cause, but later, I dindā€™t change them, but and I still see no curved tracks.

There are other curves too. Some (90 or 45 D)corners could be smooth or rounded.

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IMO Routing differential pairs is not perfect, but I think that is skill which improves with using.
That is, I think, routing Diff pairs will get easier with practise

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Definitely. But, it still has some issues that have to be addressed with code, I feel that in the past, it was easier to route these traces.

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Routing of differential pairs likely is part of the more general Push & Shove router, and the Push & Shove router gets tweaked all the time in attempts to improve it. Itā€™s likely that improvements for one part makes it behave a bit worse in other parts, and Iā€™m guessing that not each change is tested very thoroughly.

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Thanks for these comments. I thought I was doing something wrong but it looks like differential routing is still a little bit quirky. It lacks smoothness and sometimes I have to finish the connection with the singled trace router but it is still very useful. Most of the traces on my boards are differential.

I look forward to future updates.

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Pedro, we should file a bug report to get this improved, but we need to have a little better understanding to know what we are going to say. But if we donā€™t do this, devs wonā€™t know about it soon.

The router is the heart of the Kicad I suppose it should work better otherwise PCBNew is not complete.

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I think Iā€™m in favor for a bug report for improving differential pair routing, but I do not use it enough to make a good description for it and wonā€™t do this myself.

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But what to say in bug report. There is no single problem. Routing Diff routes is just hard.

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One way to write this report would be to take a similar design in 5.1.12 and in 6.0.6 and then do a screen capture of the differential router process in both. If the 6.0.6 router is much slower/more fiddly (which it feels like it is) thatā€™s a sign of a regression that can be identified as a bug.

I know thatā€™s a lot of work though, which is why I havenā€™t done it yet :stuck_out_tongue:

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