Para openSUSE Tumbleweed corra o seguinte como root:
zypper addrepo https://download.opensuse.org/repositories/home:napobear/openSUSE_Tumbleweed/home:napobear.repo
zypper refresh
zypper install openscad
Para 15.4 corra o seguinte como root:
zypper addrepo https://download.opensuse.org/repositories/home:napobear/15.4/home:napobear.repo
zypper refresh
zypper install openscad
Para 15.3 corra o seguinte como root:
zypper addrepo https://download.opensuse.org/repositories/home:napobear/15.3/home:napobear.repo
zypper refresh
zypper install openscad