--allow-multicolor-oneplate

A boolean flag (default true) that controls whether the arrange pass is permitted to place objects using different filament/extruder combinations on the same plate. When true (the default), the packer treats mixed-material co-location as acceptable and will pack objects with entirely different filament sets onto a single plate. When set to false, the packer applies a rejection cost large enough to function as a hard disqualifier to any candidate placement where the incoming object's extruder-and-filament set is not a subset of the extruder set already established on the plate. The first object placed on an empty plate is always accepted; subsequent objects must have their entire filament set contained within what is already accumulated on that plate, or be pushed to a new plate.

"Same color" for this purpose is a one-directional subset check on extruder-ID-to-material-type pairs: the incoming object's set must be entirely contained in the plate's accumulated set for the placement to be accepted. This means a single-color object can share a plate with a multi-color object that happens to use that same filament slot, but a multi-color object introducing new extruder slots would not be accepted onto a plate whose accumulated set does not already include those slots.

Another hard constraint applies independently of this flag: if two distinct TPU extruder slots would land on the same plate, a separate rejection cost fires regardless of the --allow-multicolor-oneplate setting. The two checks are exclusive branches in the scorer -- the TPU check fires first, and the multicolor subset check only runs when the TPU condition is not triggered.

This flag has no effect when arrange is not running, i.e. when --arrange 0 is in effect or when a 3MF with embedded plate positions is sliced without triggering re-arrangement.