In CAD modeling, what is included in a detailed design?

In CAD modeling, a detailed design refers to a comprehensive representation of an object or system, which typically includes 3D models that illustrate the complete geometry of the design. This allows for a thorough understanding of the design's proportions and relationships between different components. Including cross-sections provides insight into the internal structure and features of the object, facilitating analysis for manufacturing and assembly. Additionally, detailing weights within the model gives critical information regarding material selection and structural integrity, which are essential considerations in engineering and product development.

The other options do not encompass the full scope of what constitutes a detailed design. Just 2D drawings would not adequately represent the depth and complexity of a design that 3D models provide. Thumbnails of initial ideas are primarily conceptual sketches that lack the precision and detail necessary for manufacturing. Marketing strategies are unrelated to the technical specifications of a design and focus instead on how to promote and sell the product, which is outside the realm of detailed design in CAD. Therefore, only the inclusion of 3D models with cross-sections and weights aligns with the requirements for a detailed design in CAD modeling.