Timeline and Selection

Timeline and history

• Click a step to select what it made; double-click to edit it.
• Right-click a step:
  • Edit
  • Turn off (suppress) / Turn back on
  • Roll back to before this
  • Move earlier / Move later
  • Delete: warns and lists the later steps that depend on it.
• Drag a step to reorder the timeline. Moves that would break the design (a step placed before something it uses) are refused with the reason.
• Rollback marker: drag the orange marker to rebuild only up to that point. New features are inserted at the marker. Buttons: go to start, step back, step forward, go to end.
• Step states: OK, warning (yellow dot), error (red dot), suppressed, rolled back (greyed).

Undo / redo: unlimited, with named steps ("Undo Fillet 1"). A whole feature session or sketch session is one undo step; inside an open session, Undo steps back through that session's own changes.

Rebuild engine:

• Each step's result is cached, so editing feature #12 of 60 only rebuilds from #12.
• Panels preview at lower mesh quality while open and rebuild at full quality afterwards.
• Geometry runs in a background worker, so the interface never freezes.

Stable references: fillets, chamfers, shells, holes and face sketches remember their edges and faces by geometric fingerprint (position, direction, type, size), not by index. They re-attach after upstream edits. If the match is ambiguous, the feature shows a warning asking you to check it.

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Selection and picking

• Click a face, edge or sketch to select it. Shift- or Ctrl-click adds or removes.
• Hover highlights what will be picked. Edges are easy to hit (a generous pick radius), and edges hidden behind faces can't be picked.
• In a section view, the cut-away part can't be picked.
• While a feature is open, clicks feed that feature:

Open feature	A click picks
Fillet / Chamfer	Edges (toggle)
Shell	Faces to remove (toggle)
Hole	A point on a flat face (adds a hole)
Loft	Sketches (toggle, in order)
Combine	First the target body, then tool bodies (toggle)
Move / Mirror / Pattern	The body to work on

Edge and face picks during these features refer to the model as it was before the feature, shown as a faint outline, so you can re-pick an edge the fillet has already rounded.

Body commands for a selection: Hide, Isolate (show only these), Show all bodies, Delete (removes the feature that created the body).