German architecture and engineering firms bill their fees under the HOAI, the statutory fee scale for architects and engineers (Honorarordnung für Architekten und Ingenieure). In practice that means calculating across service phases 1–9, fee zones, renovation surcharges and eligible costs: complex, error-prone, and a poor fit for spreadsheets.
Projectile HOAI maps this fee logic directly into the ERP. The industry solution was built on my functional specification: together with Information Desire Software GmbH, the company behind Projectile, I defined it as a dedicated module, validated it against real project data from engineering firms and accompanied the first customer rollouts. The full story is documented as a case study.
The gap it closes
Before this solution, planning firms faced an unsatisfying choice: pure HOAI billing tools without project management, or ERP systems with no understanding of HOAI. Firms that needed both ran two systems in parallel and moved data by hand. Projectile HOAI closes that gap: fee calculation, service-phase tracking and final invoicing run in the same system as project control, without re-keying data between systems.
From master thesis to product
The functional foundation comes from my master thesis on the HOAI (International Management program). I translated the requirements of the fee ordinance into system requirements a development team can build against: data model, calculation rules, exceptions. Product definition with Information Desire Software GmbH followed, covering fee calculation, service-phase tracking and final invoicing. The module was tested against real project data before market launch, and it became the basis for Information Desire Software to open up a new customer segment.
Implementation in your firm
Today I support planning and engineering firms through implementation, using the same approach as any Projectile implementation: capture requirements with the business side, specify the configuration, run integration tests against real data, then go live with key-user training and monitoring. If accounting needs to be connected, for instance via the Projectile-DATEV interface, the data mapping is handled by the same person.