Slice 3 of common-line cutting. On costly plate (N26-295: 3/16 RA310S at about
$2,500 a sheet) pairing parts one kerf apart fits the part the spacing cannot:
the last plate's 38 parts fit on one 48x120 with Auto Nest only with pairs.
- Drawing Properties gains "Allow common line" (Drawing.AllowCommonLine, off by
default because customer edge-quality needs vary). The nest's CommonLineUsage
(Off / When it adds parts / Whenever available) is set in Auto Nest and seeded
from Tools > Nest Defaults; both persist (nest.json, defaults.json).
- NestPipeline runs the ordinary solve, then, with a level on, trials where
eligible parts are offered as kerf-gap pair compounds. Placed pairs expand into
parts plus explicit NestJobCommonLine groups, are validated again, and
CommonLineRanking keeps a trial only by the level: count first, then sheets;
"when it adds parts" keeps the plain layout on a tie, "whenever" also takes a
shorter cut or less material, never at the cost of a part. Engines, FillScore
and their comparers are unchanged; Off asks the engine exactly what it did.
- NestLayoutCheck exempts members only through a sheet's explicit group list and
only when the job allows common lines; materializing and committing create
Plate.CommonLines.
- Server nesting writes common-line jobs as version 3 and replays the recorded
trial answers, so the desktop binds the same groups.
- Fill Area honors the level through a PlateFillService overload.
- The benchmark gains --common-lines <level> --kerf <k>.
Benchmark (synthetic nests + N26-295, --parallel 1): with no flag and with
--common-lines off every engine matches the base commit; with a level on no
layout becomes invalid and three runs save a sheet at equal nested area.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>