Welcome W 5 Introduction to Engineering Design II (IE 202) Chapter 3: Defining the Client’s Desires and Requirements 1 1

Today’s Learning Outcomes By the completion of today's meeting, students should be able to: Clarify and translate the client’s requirements and interests, using attributes/objectives & constraints – functions & metrics. Practice how to construct an objectives tree. 2 2

Preview What have we covered so far? Overall design process 3 3

1st Task in the Design Process 4 4

Clients’ Problem Statements Clients usually begin the design process with problem statements that are Often verbal, or very brief [single sentence] “Design a bottle for our new children’s fruit juice product” “Design a keyboard for blind people use” “Design a long life laptop battery” “Design a villa in my 600 sq. m. land” Think about more design client statements! 5 5

Problems in the Problem St. Design eyeglasses to watch خسوف الشمس! The client problem statement may contain: Errors – incorrect, faulty information or missing key information Biases - presumptions about the problem situation that may prove to be inaccurate or reflect a limited viewpoint of the client Implied solutions - the client’s idea of how to solve the problem is specified Design a hospital near the intersection where many accidents take place! Add a new lane to solve the traffic problem! 6 6

What does the client actually need? What does he want? The designer’s aim is to know: What does the client actually need? The designer should employ the tools for the pre-processing phase of design to understand then document the design problem by: Building the Objectives Tree Attaching weights to those objectives Identifying the constraints Revising the problem statement 7 7

Problem Definition The designer should have a clearer understanding of What does the client want? What do potential users need? What technological, environmental, political, marketing and other contexts our gadget, process or project will function in? This will result in Defining our Design Problem much more clearly and realistically. 8 8

Sample Questions? What features or attributes would you like to have? What do you want it to do? Are there already ones on the market that do similar functions? What does that mean? (to clarify) Why do you want that? (to clarify) Can you think of more questions? 9 9

The Objectives Tree Can usually identify characteristics of the design space for potential solutions that are likely to be very good. The objectives tree has a hierarchical structure. It is for the object/process/project being designed, not for the design process. The top levels represent the most important goals, the lower levels branch out to describe these goals in terms of sub-goals. Reading an objectives tree downward reveals how a goal is defined (what is included in that goal). Reading an objectives tree upward reveals why a sub- goal is important (why want to do that). 10 10

Sample Objectives Tree 11 11

Attributes List Analysis Not all statements are of the same kind. Some are binary (Yes/No answers), e.g. must not conduct electricity Some are relative, e.g. inexpensive means lower price is desirable Other differences Limit on deflection is beginning to translate features into design specifications Color choice should probably be deferred until later. Is that always true? Any jokes? As a designer, why bother? So that the client comes back! 12 12

Goals and Objectives Attribute: Vacuum cleaner Expressions of desirable attributes of a design or solution to the problem that we strive to achieve – What will it ‘be’?, as opposed to: What will it ‘do’? Can often be expressed in terms of “more” or “less” of something, such as “more durable” which is better than a “less durable” design. Function: It collects dust 13 13

Sample List of Attributes 14 14

Constraints Limitations on the design which must be met for the design to be acceptable Clearly defined limits that can be thought of as binary in that they are either met or not Any design that fails to meet a constraint is to be rejected. Constraints are very important in limiting the design space and reduce the options, i.e. they tend to lead to certain design alternatives being rejected. Is that good for you? It makes me concentrate on my options 15 15

Types of Constraints Constraints may be “hard” or “soft”. In many cases, soft constraints are ones which the client may have imposed while still at an early stage of the problem definition process. They can be challenged and, in some cases, relaxed. “Hard” constraints are strict limits. 16 16

Objectives vs. Constraints Often confused and incorrectly interchanged Constraints (e.g. less than $25) allow us to reject unacceptable alternatives Objectives (e.g. inexpensive) allow us to select among designs that are at least acceptable (at least satisfies all constraints) NO If objectives & constraints are met, Does that guarantee an optimal design? 17 17

Objectives Tree The objectives tree can go as deeply as the designer chooses or finds necessary. When the point is reached that the design team is listing implementations rather than sub-goals, it is time to stop. A pruned Objective Tree is solution independent. Constraints can be re-entered in the appropriate portion of a combined tree of functions and implementations 18 18

Objectives & constraints Sample Combined Tree Objectives & constraints could be combined 19 19

Practice: Objectives Tree Determine the objectives and constraints trees for the following design problems: Public Transport System in our campus. Public Walkways for sports and leisure. Bicycles for transportation. Chairs for active learning classes. Supersonic commercial airplane. Multi-function Tablets. 20 20

Functions and Means Functions Keep the tissue moist Things the design must do Usually expressed in terms of verb-object combinations, such as “resist force” or “convert power to heat” – OR ‘doing’ Means or Implementations Ways of performing the functions that the design must do, i.e. used to attain an end Very much solution-oriented Teams: Come up with 3 functions & means. Keep the tissue moist 21 21

Presentations By 12 midnight tomorrow, each team has to send 3 ideas for the term project with few lines explaining each idea. On Wednesday, each team has to present the three ideas. The instructor will choose the most appropriate one. 22 22

Exercise # 2 – Section # Team # This is an assignment to be solved as a team. The answer should be submitted electronically. The file name for your work should be: Exercise # 2 – Section # Team # e.g. Exercise # 2 – ZZ9 – S2014 23 23