1. Developing an Objectives-Constraints Tree
Creating a graphical representation of design objectives and constraints
Taken from engineering design: a project-based introduction by dym & little

2. The development of an Objectives-Constraints Tree proceeds from the Attributes List and PCC.
The hierarchy of the Objectives-Constraints Tree comes from the results of the Pairwise Comparison Chart.
Primary objectives are listed in the first level of the tree.
Secondary objectives are grouped as subsets of the primary objectives. The same concept holds for subsequent levels of the tree.
Constraints should be listed as a subset of related objectives.
The other objectives and constraints listed in the tree come from the Attributes List.
Objectives are listed in rectangular boxes, and constraints are listed in ovals.

3. Below is an example (not exhaustive) of an Objective-Constraints Tree for a ladder design.
Safe
Stable
On floors
On level ground
Stiff
OSHA req.
Insulator
Marketable
Useful
Indoors
Electrical
Maintenance
Outdoors
Of right height
< $200
Portable
Light in weight
Small, transportable
Durable
Objectives are shown in rectangles and constraints in ovals. The hierarchy follows from the Pairwise Comparison Chart. The tree structure allows for the objectives and constraints to be categorized/grouped.
Objectives
Constraints

4. Below is an example (not exhaustive) of an Objective-Constraints Tree for a ladder design.
Safe
Stable
On floors
On level ground
Stiff
OSHA req.
Insulator
Marketable
Useful
Indoors
Electrical
Maintenance
Outdoors
Of right height
< $200
Portable
Light in weight
Small, transportable
Durable
Subsets of “safe”
Objectives are shown in rectangles and constraints in ovals. The hierarchy follows from the Pairwise Comparison Chart. The tree structure allows for the objectives and constraints to be categorized/grouped.
Subset of “marketable”
Objectives
Constraints