Path strategies

AUTO_EJECT turns the part outlines from [exclude_object] into a list of pushes. Each push moves to a start point at a safe height, lowers the blade, drives it to the drop edge, and lifts again. The strategy decides where those pushes go.

The examples below push to the front (Y-). The other directions work the same way, rotated.

Throughout, "behind" means further from the drop edge, and the start point of a push is:

start = (back edge of the part(s) in the lane) + rear_clearance + blade_offset

That puts the blade's face rear_clearance mm behind the part before it comes down.

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columns (default)

The bed is split into lanes as wide as the blade, overlapping by column_overlap. The lanes cover only the span where parts are. Each lane starts behind the rearmost part in that lane and sweeps everything in front of it off the edge.

   back ─────────────────────────────
            ↓ start      ↓ start
          ┌─────┐      ┌─────┐
          │ ▲ ▲ │      │  ▲  │        ▲ = parts
          │ ▲   │      │ ▲ ▲ │
          │  ▲  │      │     │
          └──┼──┘      └──┼──┘
   front ────┼────────────┼──────────  drop edge
             ▼            ▼

• Works with any layout. No gaps are needed between parts, because the blade always comes down behind everything in its lane.
• Parts in the same lane are pushed together, and the front ones are carried along by the rear ones. That suits small, light parts (cookie cutters, badges, clips).
• Empty stretches of bed between groups of parts are not swept.

objects

One push per part, starting with the part nearest the drop edge, so that by the time a part is pushed, everything between it and the edge is already gone.

   back ─────────────────────────────
                         ↓ 2
                       ┌───┐
              ↓ 1      │ ▲ │
            ┌───┐      └─┼─┘
            │ ▲ │        │
            └─┼─┘        │
   front ─────┼──────────┼──────────
              ▼          ▼

• Each part is pushed on its own and centred on the blade, which works better for larger parts.
• Needs room behind each part. Before planning, the macro checks that no other part sits in the area where the blade and toolhead come down (head_depth × blade_width + side_margin). If one does, it stops with an error naming both parts, before anything moves. Use columns for tightly packed plates.

full_width

Sweeps the whole bed width in lanes, every lane starting at the far axis limit. It ignores part positions, so it works without object labels.

• The slowest strategy, but the most thorough.
• Useful as no_objects_action: "full_width" for files sliced without labels.
• Verification is skipped, because there are no part positions to probe.

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Choosing

Your plates look like…	Use
Many small parts, packed tightly	columns
A few larger parts with space between them	objects
Files from a slicer without object labels	full_width

You can override the strategy for a single run: AUTO_EJECT STRATEGY=objects.

Edge cases the planner handles

• A part close to the far edge. If the start point would be beyond the axis limit, the blade cannot get behind the part. The macro stops with an error, unless allow_clamped_start: True.
• Lanes near the side limits. Lane centres are clamped to the cross axis travel. The blade width still covers parts at the very edge as long as the blade is wider than the gap.
• Probe offsets are applied only during verification. Pushing is planned for the nozzle position plus blade_offset.