4D Scheduling & 5D Cost Model in OpenConstructionERP

Concepts

• 4D = schedule + BIM: every task can reference BIM elements so the sequence is visual.
• 5D = schedule + cost: cost roll-ups per task/phase from linked BOQ lines.
• Both live on the same task graph — one source of truth for time and money.

Workflow

1. Build the task graph — tasks, durations, dependencies (FS/SS/FF), milestones, critical path.
2. Link BIM elements to tasks (from oce-bim-takeoff) — visual sequencing and progress colouring.
3. Link BOQ lines to tasks (from oce-estimate-boq) — each task carries its direct cost.
4. Roll up — phase/project totals, cash-flow curves (cost over time), SPI/CPI views.
5. Track — daily diary entries and punch items update actuals; variance reports compare plan vs actual.

Key endpoints