Nest a backlog of sheet-metal parts together — several orders, materials and thicknesses at once — to learn what each order and each part costs on the sheets they share. Name the calculations (items: calculation_id, and optionally quantity — the lot size when omitted — order_ref, due, priority), OR a batch_id, OR a folder_id; each calculation must be of a sheet-metal part priced in environment_id. By default (apply=false) this PLANS only: it returns what the job nest would take — the lines and copies of each material and thickness, the remnant pieces of it in stock, and what a batch or folder leaves out and why — and starts nothing. Call again with apply=true to start it (needs parts:write); it runs in the background: poll arcnm_nest_run_status, then read arcnm_nest_run_result. When this month's runs are used, apply=true keeps the job nest as a draft instead — stored, not queued, spending no run — and arcnm_nest_run_start starts it later; the plan says so first (kept_as_draft). A job nest takes every remnant it cuts from out of stock and puts its reusable rests in, so each one started uses stock; the same call within 24 hours answers the job nest it already started. It never changes a calculation's own price.