APPROVal of Engineering Design models

Research Review 2018

A vessel-specific standard addressing the information needs of the Classification Society is a key enabler to replace traditional 2D drawings with a 3D model as design documentation submitted for verification.

"The vision of the APPROVED project is aligned with our ambitions as a design company to further reduce costs and time to market for our innovative design solutions. We see this can strengthen our competitiveness. The project also supports our goal to strengthen the interaction among stakeholders in the production and supply chain by utilizing the 3D model as an information carrier."

Bernt-Aage Ulstein

Director Design & Engineering

Traditionally, drawings are used for communicating designs in the industry because they are the clearest way to tell a human what to make and how to make it. Technical drawings provide a means to communicate product complexity in a comprehensible and effective manner thanks to visual abstraction. In shipbuilding, it is still an explicit requirement that the designer/yard shall provide the Classification society with Class drawings documenting the design to be approved to the Society’s Rules.

At the same time Computer Aided Design (CAD) models are now displacing technical drawings and documentation as the main product definition in several major industries. Within the last ten years or so, the engineering industry in automotive, aerospace and construction has gradually converted to using CAD models directly for communicating designs to manufacturers, builders, maintenance crews and regulators. This switch to creating the engineering record in models, however, presents problems not only for its long-term maintenance and accessibility – due in part to the rapid obsolescence of the hardware, software and file formats involved – but also for recording the evolution of designs, artefacts and products.

Both the aviation and automotive industries are moving towards a drawing-free product lifecycle. DNV GL sees several drivers in this development:

  • One master product definition
  • Virtual prototyping and simulation
  • Computer-aided manufacturing (CAM)
  • Assembly automation
  • Production of maintenance documentation
  • Earlier coordination of design activities

The key to achieving interoperability across software applications is open standards, i.e., those developed by consensus either within a standards development organization or a consortium of stakeholders. No single software tool can perform all the engineering tasks needed to design and manufacture a product to a sufficient standard. Users will mix and match software products matching their business objectives. Standards define an agreed-upon syntax and semantics of 3D modelling constructs and annotation so that users can understand one another’s models and design intents.

3D models will replace traditional drawings for approval of ships

Shipyards and classification societies must modify the traditional design documentation and review process and enable direct 3D digital classification process to improve the exchange of information between the different stakeholders and ultimately accelerate the classification process. Compared to traditional drawing approval, the advantages include:

  • Reducing shipyard workload with fewer drawings to create
  • Improving quality and a common understanding of design and class comments by using a 3D design representation directly
  • Optimizing the calculation process by directly interfacing the 3D design model with all calculation software such as structural and stability software
  • Improved transparency and support for automation and increased self-service

The development of such a standard has been a key activity in the APPROVED project. The standard, or data schema, has been named Open Class 3D Model Exchange (OCX) and is intended to become an open industry standard for the exchange of design information between designer/yards and classification societies. The goal of the standard is to replace traditional 2D class drawings with a 3D model of the design as design documentation. The OCX standard is unique in the sense that it specifically addresses the needs of the classification society and shipbuilders for a fully digital information exchange. There is currently no corresponding unified industry standard in use by the shipbuilding industry. As the OCX standard will be implemented by three of the major ship system design (CAD) providers, there is a legitimate hope that this standard will become the unified standard for the entire maritime industry.