Step 1: Understanding the Question:
The question asks us to identify which stage of a design project utilizes physical cardboard mockups and digital 3D renderings.
Step 2: Key Formula or Approach:
The prototyping process runs along a spectrum of detail, from low-fidelity physical models (like cardboard mockups used to test scale) to high-fidelity digital models (like photo-realistic 3D renderings used to evaluate aesthetics).
Step 3: Detailed Explanation:
Both 3D digital renderings and physical cardboard models are core parts of the Prototyping process (Option C). They serve as early, inexpensive versions of the product that allow the team to evaluate, share, and test their concepts before committing to final production. They are not part of basic documentation (A) or scenario planning (B).
Step 4: Final Answer:
These models are part of the prototyping process, corresponding to option (C).