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Re: [RFC]: New non copper pad paste and mask clearances behavior

 

Pragmatism is the reason I've asked JP to create this patch. Rather than create a lot of extra work for our librarians and creating a file format change that doesn't really buy us much, I reconsidered my original decision. I doubt many users are currently using "aperture pads" so I think the risk is low and the longer we push this off, the greater the problem will be. I already have an announcement prepared for the website once this makes its way into the repo. I will also post a link to the announcement on the user forum and update the Pcbnew documentation.

On 05/02/2018 05:11 PM, Jeff Young wrote:
Personally I think this is one of those times to be pragmatic.  Yes, the patch changes the interpretation of existing files (which in principle is a bad thing), but we’re willing to live with it in this case.

I don’t have much of an opinion on the exact algorithm we should use.

Cheers,
Jeff.

On 2 May 2018, at 21:57, Eeli Kaikkonen <eeli.kaikkonen@xxxxxxxxx <mailto:eeli.kaikkonen@xxxxxxxxx>> wrote:

The patch seems to work as intented.

But I thought Wayne said this won't be done because it would alter interpretation of old existing board and footprints files. On the other hand it's hard to imagine someone having designed footprints and boards using and taking into consideration the global values, without noticing and using this trick of using a very small value instead.

If this kind of change is made I think a more radical change would be more logical. Why use these clearances for non-copper pads at all? I just can't see why I or anyone would design a pad with certain dimensions and then alter those dimensions on purpose with those clearance values. For example I want a paste pad of 1.5x1.5mm. Why would I make it 2.0x2.0 and then calculate values for paste clearance and % to make it smaller? Being able to define the mask clearance for a paste-only pad makes even less sense. Therefore they could be ignored completely and the corresponding GUI items could be disabled or hidden. Instead of one explanation text which would cover all cases with all pads it could be conditional: in the copper pads it would read as it is, in the non-copper pads it would be "Clearance values are not used for non-copper pads" or something as simple.

Eeli Kaikkonen

2018-05-02 15:58 GMT+03:00 jp charras <jp.charras@xxxxxxxxxx <mailto:jp.charras@xxxxxxxxxx>>:

    Hi All,

    Dick Hollenbeck ( who wrote a lot of code for Kicad) proposed to
    use global mask margin values only
    for pad at least on a copper layer.

    (I am thinking this is also what was expected by some of guys)

    Attached, a patch to use global mask settings only for pads on
    copper layers to build the mask shape
    (solder or paste layer) of the pad.

    Therefore pads *only* on a solder or paste layer are no longer
    affected by global settings.
    (The drawback is a change in the behavior of previous Pcbnew
    versions, but it should not impact a
    lot of old boards or old footprints)

    The change in code is very small.

    I added a info message in dialogs, in the pad clearance setup
    sub-window to explain the purpose of
    this setting.
    This is perhaps the main problem, because a message in a dialog
    must be short, and yet understandable...
    The info messages are not perfect.

    Please, test it.

-- Jean-Pierre CHARRAS

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