Offcuts

Most ERPs treat offcuts as scrap. Rubberfit treats them as first-class inventory: searchable, reusable, and reached for automatically before the engine pulls a fresh roll.

This is the single biggest material-yield lever in the platform. Customers report 15–25% of small-part demand satisfied from offcut stock without ever opening a new roll.

A 120″ roll fragments into four labeled offcuts after a cut commits — each retains parent_roll_id lineage.

The offcut record

The inventory.offcuts table stores them. Key columns:

Column	Notes
`id`	UUID
`parent_roll_id`	FK back to the roll this came from
`parent_cut_id`	FK to the `cut_history` row that produced this offcut
`polygon`	The geometric shape of the offcut (irregular, JSONB array of points)
`area_mm2`	Computed from polygon at creation
`material_id`	Inherited from parent roll
`created_at`	UTC timestamp
`consumed_at`	NULL until the offcut is itself cut
`status`	`available` / `consumed` / `discarded`

Generation

Offcuts are generated automatically when a cut commits. The engine’s final pass:

Computes the bounded leftover regions of the roll after all parts are placed
Filters out regions smaller than the workspace’s offcut threshold (default 0.05 m²)
Triangulates each remaining region into a stable polygon
Inserts an inventory.offcuts row with full geometric data

How the engine uses them

When you press Pack on a job, the Auto Nest pre-pass:

Gets the list of parts and their bounding-box areas
Queries inventory.offcuts for material_id = job.material_id and status = available
Filters offcuts whose area_mm2 is at least 1.2× the smallest required part area (a safety factor)
Tries those offcuts before pulling a fresh roll, lowest-area-first

If the engine can satisfy the entire job from offcut stock, the operator sees an “All from offcuts” badge in the layout preview. Otherwise the engine combines offcuts + fresh stock as needed.

Manual override

Operators can override the engine’s choice by clicking Choose stock and selecting specific rolls or offcuts in the assignment modal. This is useful for:

Rush jobs where speed matters more than perfect yield
Customer-specific lot requirements
Defect avoidance — pulling a known-clean offcut over a roll with a flagged region

The engine’s offcut search ignores offcuts that are too irregular to fit any of the requested parts. Geometric eligibility is checked at solve time, not at the dashboard query level.

Lineage display

/dashboard/inventory/offcuts/[id] shows:

The parent roll and the originating cut
The cut history of any cut that consumed this offcut
A visualization of the offcut polygon overlaid on its parent roll

This is what makes offcut reuse defensible to a quality auditor: every offcut traces back to a roll, every consumed offcut traces back to a cut.