MarsSeed [1] filed a deletion request for openmeca-git [2]: Abandoned, broken Qt5-based PKGBUILD from 2020. Not compatible now with the Qt6-based AUR/libqglviewer.
(Also it seems upstream has not been maintained for 2 years.) [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/openmeca-git/
