Separate appearance, behavior, and construction
A prototype can look finished while containing a simplified mechanism. It can function realistically while having an unfinished enclosure. It can represent a control sequence accurately without containing the system that will eventually carry it out.
These are separate aspects of fidelity. Describe each important aspect in relation to the question being investigated. A broad label such as “working prototype” is not enough to establish whether the object is suitable for a handling review, a performance trial, or a manufacturing discussion.
Name every important substitution
A substitution changes the relationship between the model and the intended solution. A different material, an external power supply, manually entered data, or a simulated response may be entirely appropriate for early learning. The review needs to know where these choices matter.
Record the substitution, its purpose, and the conclusions it prevents. If the model uses an external connection that will not exist in the final arrangement, observations about portability or installation may be limited. If timing is simulated, the model cannot establish actual response performance.
Use the boundary to plan the review
The review scenarios should exercise the represented aspects without quietly depending on the missing ones. Explain the scenario to participants and observers in plain language. Avoid presenting a staged response as an automatically achieved result.
Capture requests that fall outside the prototype’s purpose. Those requests can reveal useful needs, but they do not automatically become build requirements. The team should decide whether to change the prototype, create a different representation, or leave the question for a later phase.
Update the boundary when the prototype changes
A revision may improve one aspect while changing another. Maintain an identifier and a short change note so observations can be connected to the correct configuration. Keep the purpose statement with the item rather than relying on an explanation that only the original builder remembers.
A simple boundary sheet can list the question, realistic aspects, simplifications, supported review activities, and excluded conclusions. It can travel with the prototype and remain part of the decision record after the physical or digital representation has been replaced.