Exploring the Design Space

1. Exploring the Design Space V. V. Kamat Department of Comp.Sc & Technology Goa University vvkamat@unigoa.ac.in

2. Agenda • Design issues in General • Design posed as a search problem • Some design problems from Animation • How good is the Design? • Design frameworks • Conclusion Exploring the Design Space @ DA-IICT

3. Design: Designer’s Perspective • Design evolves over time • Design needs to be evaluated • Design involves competing forces • Design is knowledge intensive • Design errors are expensive • Design need to be cost effective • Design needs to be flexible/reusable Exploring the Design Space @ DA-IICT

4. Design: User’s Perspective • Design is simple to understand • Design is easy to use for novice & expert • Design is functionally superior & robust • Design is esthetically superior & pleasing • Design is affordable Exploring the Design Space @ DA-IICT

5. Current Trend • Product life-cycle is shrinking • Market demands better design at lesser cost • Design and production not under single roof • Greater integration in Design & Production • Design is going digital Exploring the Design Space @ DA-IICT

6. Issues related to digital design • Storage - Compression & Transmission • Security - Authenticity & Protection • Quality – Testing & Certification • Visualization – Look & Feel Exploring the Design Space @ DA-IICT

7. Design is Problem Solving • Behind design there is an abstract idea • Design is a solution to one/more problems • More than one design/solution likely • Design space is all probable solutions • Not all solutions are good • Constraints help in selecting solutions Exploring the Design Space @ DA-IICT

8. Design Strategy • Systematically search in design space • Generate a solution & test its validity • Explore design space for valid solutions • How many solutions are there? • Search for a solution in design space can be posed as an optimization problem Exploring the Design Space @ DA-IICT

9. Optimization Problem • Given a set of design variables, and set of design constraints, find a solution that best satisfies design constraints • Analytical solution are not always possible • Numerical solutions are preferred • More than one solution may exist Exploring the Design Space @ DA-IICT

10. Search for good design solutions Good Solution Design Space O O X X X X X O O Bad Solution Exploring the Design Space @ DA-IICT

11. Solving Linear Equations Searching for a Solution l o l m d d d d d n m n o x Minimum distance d using gradient search method Exploring the Design Space @ DA-IICT

12. Eight Queens Problem • Eight queens are to be placed on a chess board in such a way that no queen attacks any other queen • A queen can attack another queen if it is in same row or same column or same diagonals • No analytic solution to the problem • Solutions are systematically searched in the design space using backtracking Exploring the Design Space @ DA-IICT

13. One Correct Solution Exploring the Design Space @ DA-IICT

14. Solution 1 = [2, 4, 1, 3] Solution 2 = [3, 1, 4, 2] Reduced Problem state 4 X 4 Exploring the Design Space @ DA-IICT

15. Articulated Body Animation • Given an articulated figure, design walking motion such that it looks physically correct and natural • Each limb is a rigid body and has 1-2 degrees of freedom Tree-like body Exploring the Design Space @ DA-IICT

16. Given a 2-D linked structure, design a controller which defines at every time step t, a4-tuple (x, y, θ1, θ2) such that it satisfies trajectory constraints Toy example P(t) θ2 θ1 (x, y) Exploring the Design Space @ DA-IICT

17. Articulated Body Animation • Constrains could be kinematic or dynamic • Problem has a curse of dimensionality • Search for a controller involves solving a large constrained optimization problem using inverse kinematics or dynamics Exploring the Design Space @ DA-IICT

18. Articulated Body Animation • Search space is multimodal & discontinuous • Problem is solved as large constrained optimization problem using stochastic search • Simulated annealing • Genetic algorithm • Stochastic hill climbing Exploring the Design Space @ DA-IICT

19. Given deformable objects design variety of walking motion that is physically correct and natural Deformable object is represented by mass points connected using spring & damper Flexible body Animation Exploring the Design Space @ DA-IICT

20. Given a deformable object made of 4 mass points, design a controller that generates walking motion Deformable object should interact with environment that looks natural Toy Example Mass points Spring-damper Exploring the Design Space @ DA-IICT

21. Flexible body Animation… • Each mass point is acted upon by • Forces from neighboring points (f = -k x) • Forces due to gravity (f = mg) • Forces due to collision & friction (f = -kpx - kfv) • All forces on the mass points are added and motion equation is solved • Design involves searching for a controller that can bring about interesting motion Exploring the Design Space @ DA-IICT

22. How good is the Design? • Design is as good as it tests (taste?) • Design needs to be tested thoroughly with test cases / scenarios • Each test case / scenario tests only part of the design against specifications • Exhaustive testing is impossible • Can the design be proved / verified for correctness? Exploring the Design Space @ DA-IICT

23. Designer designs, Tester tests • Designer designs with test cases in mind • Design errors manifests itself into bugs • Tester uncovers design bugs by subjecting the design to various tests • Tester add value through constructive destruction • Digital design, allows testing to be done in software Exploring the Design Space @ DA-IICT

24. Design Pattern • Years ago architect named Alexander asked • Is quality objective? • How one can identify good architectural designs? • Alexander postulated that • Objective basis can identify good / bad designs • All good / bad designs share a pattern Exploring the Design Space @ DA-IICT

25. Design Pattern • Problems in design that occur over and over could be solved in some what same manner • Creating a catalog of solutions to known problems • Using this catalog of design patterns, specific designs solutions could be tailored • Creating strategies and approaches for addressing common design problems Exploring the Design Space @ DA-IICT

26. Design Framework • Design patterns will help the designers communicate designs at more abstract level • Avoiding common pitfalls in design • Design Frameworks is a software that will embody design patterns in specific domain • Creating a wealth of knowledge Exploring the Design Space @ DA-IICT

27. Design Patterns & Framework • Patterns support reuse of design ideas • Frameworks support reuse of detailed design • Design pattern and frameworks together help to improve on quality of design and reduce development time Exploring the Design Space @ DA-IICT

28. Patterns of Learning • Successful solutions to many areas of human endeavor are deeply rooted in patterns • Goal of education is transmitting patterns of learning from generations to generations • What are the learning patterns in playing the game of chess? • Learning to design is similar to learning to play chess Exploring the Design Space @ DA-IICT

29. Becoming a Master • First learn the rules • Then learn the principles • However, to become a master designer, one must study the designs of the other masters • There are hundreds of these design patterns • Future lies in building domain specific frameworks Exploring the Design Space @ DA-IICT

30. Conclusion • Design is 20% creative and 80% repetitive • Digital design – Sky is the limit • Designing & Testing complement each other • Domain specific frameworks to provide next generation design productivity tools Exploring the Design Space @ DA-IICT

31. Questions ? Thank You!