Improvements to chamfered pads

[Rene Poeschl]

To fully implement what we need to replace our workaround for https://bugs.launchpad.net/kicad/+bug/1777516 the chamfered corners would need to be rounded as well if there is a round radius given.

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For our usecase it would be enough to have everything rounded with the same radius (And the chamfer converted to a normal rounded corner if the chamfer size would be too small for the given radius.) See attachement

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A possibly more flexible approach would be to be able to select which corners to round and which ones to chamfer with both being possible options at the same time.

This would allow this generalized pad to cover things like single sided oval as requested in for example https://bugs.launchpad.net/kicad/+bug/1814039

[Michael Kavanagh (michaelkavanagh)]

I've set the milestone to match the one in the related bug report linked by @Rene, so they can be considered together.

[Rene Poeschl (poeschlr)]

If done right then the chamfered pad can even generate triangle pads with a right angle as requested in for example https://bugs.launchpad.net/kicad/+bug/1778622

[Seth Hillbrand (sethh)]

Hi Rene-

Do you have some reason to believe that IPC 7351-C will recommend rounded corners _on_ the chamfers? I haven't seen that anywhere.

-S

[Rene Poeschl (poeschlr)]

IPC only talks about simple pad shapes (based on simple rectangles). Chamfers are used where one can not achieve the necessary clearance otherwise (corner pads of some qfn packages are an example)
I would however assume that the same reasons for using rounded corners on normal corners apply also for ones on chamfered ones. (Easier paste release and better solder flow)
It also looks strange otherwise. But you are right it is not written in stone that it is needed.

As i wrote above allowing the controls i suggest would make this pad type quite versatile over all. (Making implementing ever more pad shapes unnecessary.) As long as we decide to go that way before the v6 release we should not run into the trouble of needing to support the current version if we only decide this after v6 then we will need to think about a forward compatibility mode. (This is the main reason why i would choose the most generic option.)

[KiCad Janitor (kicad-janitor)]

KiCad bug tracker has moved to Gitlab. This report is now available here: https://gitlab.com/kicad/code/kicad/-/issues/2383