Operational Specifications & Safety Design

◎Merge — Basic Modes #

▼Three modes available #

• First: Merge to the first selected vertex
• Center: Move to the centroid of the selection
• Last: Merge to the last selected vertex

For details, see “Merge”.

◎UV Behavior #

▼Preserve UVs: ON #

• Without seams: fully copy UVs, align, then merge (minimizes offsets).
• With seams: delegate to Maya’s native “Preserve UVs” behavior.

▼Preserve UVs: OFF #

• With Preserve UVs off: fast processing with no UV coupling.

See “Preserve UVs” for details.

▼Automatic Unpin #

• UV Pin/Unpin: automatically toggles pinning when switched ON/OFF.
• Auto Unpin: when ON, merging automatically unpins the merged vertices (UVs).

See “Auto Unpin UVs” for details.

◎Quick Mode Behavior #

• When Quick Mode is ON, you can also merge by clicking in the viewport in addition to the Merge button.

See “Quick Mode” for details.

◎Preflight #

• On vertex selection, detect if the merge would produce non-manifold/lamina or other error meshes.
  (Configurable as Warn-only or Hard Block.)

▼Warn only
　Use when you prefer to defer cleanup and continue editing. #

▼Hard block
　Use when you must prevent creating error meshes. #

◎Dangerous Selection Detection #

• Treat “Select All”–“Select All-3 vertices” as dangerous; stop in advance with a message.
  (If below the danger threshold, merge is ready.)

• If “Max Vertex Count” or “Max UV Set Count” is exceeded, stop beforehand with a message.
  (Defaults exist for load control; configurable.)
  Note: PolyMate Merge Light (free) lacks this feature and applies fixed caps.

• If vertices from multiple objects are selected, stop in advance with a message.

• If the reference vertex for the merge is deselected, stop in advance with a message.

◎Automatic Rollback #

• Preflight and dangerous-selection detection capture errors in advance as much as possible, but to cover rare misses,
  if Maya detects errors such as geometry loss, it automatically Undo-restores to the state just before the merge.

Note: These measures are effective but do not guarantee complete avoidance/detection under all selections and scene structures. #

◎Session Hygiene #

▼Designed to avoid slowdown, breakage, or unintended actions during long use. #

• Reentrancy guard: pause re-execution and watchers during processing to prevent double triggers.
• Job/Callback management: centralized register/unregister; fully released on exit.
• Panel cleanup: detect panel switch/close/rename and unhook immediately.
• Temporary-setting restore: confine changes to the processing scope and revert on completion.
• Safe recovery on error: automatic Undo → keep edit mode → short operation lock to prevent repeated mis-operations.
• Notifications: messages auto-dismiss over time; selection or mode is not changed.
• Cache hygiene: cache only where needed; clear safely on switch/exit.
• Multiple-instance suppression: reuse/bring-to-front the same window to avoid state splits.
• Collision avoidance: separate settings and temp files with unique prefixes to avoid interference.
• No-pollution policy: do not create resident nodes; leave no residue after the session.
• Startup cleanup: detect leftovers (jobs/filters, etc.) from the previous run and remove them first.