OSE follows Module Based Design.
This allows multiple parts of an artifact to be developed in parallel, and it allows these parts to be produced in parallel via a 'barnraising'-style social production model.
To achieve Module Based Design - a machine/artifact first needs to be broken down into modules. These modules must be designed such that they fit together with other modules. For this to happen, a clear interface design must be presented.
While we discuss point product development here - modular breakdown is a more general term. It refers to the breakdown of a problem into parts that are as small as possible, so that the largest possible team can engage in parallel - to produce rapid development, or to achieve things never before possible due to the effort or coordination required. Now coordination is an issue that must be resolved - and its resulution starts with a shared culture of understanding of the nature of modular breakdown and its capacity to solve large problems. The ultimate challenge is emergent phenomena which cannot be predicted at the stage of organizing a swarm, as in General Principles of Swarm Development. The ultimate solution is the ability of individuals to problemsolve - based on a shared understanding of collaborative development.
Modular Breakdown as Technical Design
Once we have defined Conceptual Design, we can proceed to further refinement of concept towards a technical design. Upon sufficient refinement, there is sufficient information to manifest the technical design in the form of 3D CAD. The Modular Breakdown step is where the concept can be refined further by examining the constituent modules. The Modular Breakdown is the best place to capture the transition from concept to the actual design. Once the actual design (3D CAD) is produced - we can do full Calculations including structural, thermal, fluid, and electromagnetic. Partial calculations can be made at the phase of conceptual design - with back of the envelope calculations just to get an idea of basic feasibility. All of these steps can be done at various levels of product-service system organization: the system, machine, module, and submodule (part) levels.