Rhino 3D Tip: SelDup and SelLast: Remove Exact Duplicates and Reselect Recent Geometry

Speed up selection workflows by mastering SelDup and SelLast.

SelDup instantly finds and selects duplicated geometry that occupies the exact same space. SelLast selects the most recently created or modified objects. Together, they reduce clicks, prevent mistakes, and keep models clean—especially when importing or iterating quickly.

• SelDup (Select Duplicates)
  • Use when you suspect stacked curves, surfaces, or meshes (common after DWG/STEP imports or repeated copying).
  • Selects exact geometric duplicates regardless of layer or color; visibility and lock state still apply.
  • Great for cleaning 2D drafting before extrusions and for ensuring single, watertight contour sets.
• SelLast (Select Last)
  • Instantly reselects the geometry you just created or changed—perfect after commands that deselect on completion.
  • Speeds up iterative transforms (e.g., Move, Scale, Rotate) and rapid property edits in the Properties panel.

Core use cases:

• Imported CAD cleanup: Run SelDup then delete to remove stacked lines and coincident faces before Booleans.
• Curve prep: After projecting and trimming, run SelDup to ensure there’s one clean curve per profile.
• Iteration loops: Use SelLast to immediately tweak the thing you just created (e.g., a Loft, FilletEdge, or Array).

Super-fast macros and aliases (use underscore-prefixed commands for language-agnostic macros):

• Delete duplicates in one click (alias: dd)
  • Macro: ! _SelDup _Delete
  • Tip: Map to a toolbar button or a simple alias via Tools > Options > Aliases.
• Reselect last and move with Gumball (alias: lm)
  • Macro: ! _SelLast _GumballToggle _GumballRelocate
  • Tip: Turn Gumball back off if you prefer a minimal UI.
• Select last and lock (alias: slk)
  • Macro: ! _SelLast _Lock
  • Use for protecting reference geometry you just generated.

Power tips:

• Combine with the Selection Filter panel to target only Curves, Surfaces, or Meshes before running SelDup.
• After SelDup, run Invert and Hide if you want to isolate only the unique geometry for inspection.
• SelPrev complements SelLast—if you lost a selection set, SelPrev restores it quickly.
• NamedSelections are ideal for saving recurring sets after using SelDup to sanitize inputs.

Gotchas to watch for:

• Hidden, locked, or off-layer objects are ignored—make them visible/unlocked to include them.
• Blocks: SelDup does not evaluate inside block definitions; edit or explode blocks if needed, then remake the block.
• Tolerance matters: near-duplicates that aren’t exactly coincident won’t be caught; check model tolerance if imports look messy.
• Attributes: duplicates can carry different layers or materials—confirm before deleting if attributes matter downstream.

Keep your pipeline efficient: clean selections and quick reselection lead to fewer Boolean failures, tidier Make2D results, and faster edits. For more Rhino best practices, licensing, and plugin options, visit NOVEDGE or explore Rhino solutions at NOVEDGE’s Rhino collection.