Zone clearance to rounded rectangular pad incorrect

[Jules Souren]

See original thread for pictures and additional info: https://forum.kicad.info/t/abnormal-zone-to-pad-clearance-for-rrect-pad/15055/4

A rounded rectangular pad with thermal spokes does not have the correct copper zone clearance, and an unexpected keepout is created, the size of which depends on the corner size of the rrect pad.

To reproduce:
- Create a rounded rectangular pad with a corner size of 25%.
- Create a zone connecting to this pad with thermal spokes, default clearance settings are ok.
- Fill the zone, and observe the additional unexpected clearance in the corners.
- Change the pad corner size to 1%.
- Refill the zone, and observe the clearance being reduced to what is expected.
- Change the pad to a rectangular or oval pad size, and the clearance is always adhered.

For solid connection zones there is no problem, obviously - only for thermal spoke connections.

Application: kicad
Version: (5.0.2)-1, release build
Libraries:
    wxWidgets 3.0.4
    libcurl/7.61.1 OpenSSL/1.1.1 (WinSSL) zlib/1.2.11 brotli/1.0.6 libidn2/2.0.5 libpsl/0.20.2 (+libidn2/2.0.5) nghttp2/1.34.0
Platform: Windows 8 (build 9200), 64-bit edition, 64 bit, Little endian, wxMSW
Build Info:
    wxWidgets: 3.0.4 (wchar_t,wx containers,compatible with 2.8)
    Boost: 1.68.0
    OpenCASCADE Community Edition: 6.9.1
    Curl: 7.61.1
    Compiler: GCC 8.2.0 with C++ ABI 1013

Build settings:
    USE_WX_GRAPHICS_CONTEXT=OFF
    USE_WX_OVERLAY=OFF
    KICAD_SCRIPTING=ON
    KICAD_SCRIPTING_MODULES=ON
    KICAD_SCRIPTING_WXPYTHON=ON
    KICAD_SCRIPTING_ACTION_MENU=ON
    BUILD_GITHUB_PLUGIN=ON
    KICAD_USE_OCE=ON
    KICAD_USE_OCC=OFF
    KICAD_SPICE=ON

[Nick Østergaard (nickoe)]

Please add version information and test on nightly if possible as well.

[Seth Hillbrand (sethh)]

This is perhaps a misunderstanding in terms.

Clearance: The distance between different nets

Thermal Clearance: The distance between copper of the same net needed to limit thermal flow.

You set the thermal clearance separately as it serves a separate purpose.

[Seth Hillbrand (sethh)]

Hmm... I was too hasty in reviewing this.

I see now that the rrect does in fact take the clearance to be from the rectangle corner rather than an expanded polygon of the rounded rectangle. We should adjust this in v6.

[Jeff Young (jeyjey)]

Fixed a few weeks ago with the new zone fill algorithm.