Cannot create unit vector from zero length vector

c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/plugins/tt_cleanup_CN_v3.4.3_r27.pizi/TT_CleanUp/core.rb:929:in `parallel?’ c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/plugins/tt_cleanup_CN_v3.4.3_r27.pizi/TT_CleanUp/core.rb:929:in `face_safe_to_merge?’ c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/plugins/tt_cleanup_CN_v3.4.3_r27.pizi/TT_CleanUp/core.rb:917:in `block in edge_safe_to_merge?’ c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/plugins/tt_cleanup_CN_v3.4.3_r27.pizi/TT_CleanUp/core.rb:917:in `each’ c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/plugins/tt_cleanup_CN_v3.4.3_r27.pizi/TT_CleanUp/core.rb:917:in `all?’ c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/plugins/tt_cleanup_CN_v3.4.3_r27.pizi/TT_CleanUp/core.rb:917:in `edge_safe_to_merge?’ c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/plugins/tt_cleanup_CN_v3.4.3_r27.pizi/TT_CleanUp/core.rb:865:in `merge_connected_faces’ c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/plugins/tt_cleanup_CN_v3.4.3_r27.pizi/TT_CleanUp/core.rb:574:in `block in cleanup!’ c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/libs/tt-lib/TT_Lib2/model.rb:155:in `block (2 levels) in each_entity’ c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/libs/tt-lib/TT_Lib2/model.rb:153:in `each’ c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/libs/tt-lib/TT_Lib2/model.rb:153:in `block in each_entity’ c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/libs/tt-lib/TT_Lib2/model.rb:149:in `each’ c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/libs/tt-lib/TT_Lib2/model.rb:149:in `each_entity’ c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/plugins/tt_cleanup_CN_v3.4.3_r27.pizi/TT_CleanUp/core.rb:739:in `each_entity_in_scope’ c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/plugins/tt_cleanup_CN_v3.4.3_r27.pizi/TT_CleanUp/core.rb:571:in `cleanup!’ c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/plugins/tt_cleanup_CN_v3.4.3_r27.pizi/TT_CleanUp/core.rb:451:in `block in show_cleanup_ui’ c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/libs/tt-lib/TT_Lib2/inputbox.rb:183:in `event_inputbox_close’ c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/libs/tt-lib/TT_Lib2/inputbox.rb:164:in `close’ c:/users/onlytime/appdata/roaming/sketchup/sketchup 2020/sketchup/plugins/pizi_dialog/libs/tt-lib/TT_Lib2/inputbox.rb:164:in `event_inputbox_accept’

2020报错