Editing Bottom-up and top-down design (section)

=== Product design and development ===
{{Main article|New product development}}
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During the development of new products, designers and engineers rely on both bottom-up and top-down approaches. The bottom-up approach is being used when off-the-shelf or existing components are selected and integrated into the product. An example includes selecting a particular fastener, such as a bolt, and designing the receiving components such that the fastener will fit properly. In a top-down approach, a custom fastener would be designed such that it would fit properly in the receiving components. For perspective, for a product with more restrictive requirements (such as weight, geometry, safety, environment), such as a spacesuit, a more top-down approach is taken and almost everything is custom designed.