CS 285: SOLID MODELING

Lecture #2 -- Mo, Jan. 23, 2006.

Last Lecture:

• What is CS 285 all about ?
  -- creating CAD models by using programs, exploiting symmetries, and other geometrical constraints/relationships.
  
• What is a Solid ?
  -- has a well-defined surface; maintains the connectivity of that surface with some cohesiveness ==> allows to be described with a B-rep.
  
• What are the kinds of things that fit into CS285 ?
  -- YES: scanned objects, machine parts, toys, sculptures, snap-together parts, bone models, sea shells, tree trunks, math models, and many more ...
  -- NOT: clouds, water, fire, forests, rainbows ...
  
• What are the various steps in the Design Process
  -- from an idea to a prototype ...
  -- explore a couple of the initial steps in Assignment #1.
  

The Design/Modeling/Prototyping Process

1. The Creative Spark  (--> a personal mental image)
   Where do you get your best ideas?
   What can you do to enhance the creative flow?
   Shockley's model of the "creativity pump" in the brain.
2. Initial Sketch or Mock-up  (--> something that others can see)
   How do you visualize, realize your ideas?
   What materials may be useful to make conceptual models?
3. Transformation into a CAD model  (--> something a computer can read)
   How do you get those ideas into the computer?
   ==> Discussion of homework assignment.
4. Implementation Concerns  (--> something a computer can "understand")
   What do you need to do to turn that data into a solid model?
5. Design Refinement  (--> something that can be physically realized)
   Enter the concerns about fabrication.
6. Rapid Prototyping  ( something that can be built on a RP machine)
   What are the possibilities?

Possible Course Projects

• Design Something that Can Be Fabricated:
  
• Fancy casing for a wearable computer
  
• 3D visualization model of complex geometry
  
• Snap-together mechanism
• Build a CAD model to be explored by simulation:
• Strength / sound analysis on a mechanical part
• Manufacturability analysis of an injection mold
• Parameterized Objects (perhaps to be optimized by human judgment)
• Ornaments, Sculptures, Bells, ...
• Build Some Software Utility that acts as a stepping stone for other projects:
  
• Add a special "Warp-Module" to SLIDE
• Add a surface modification module to SLIDE, that can make perforated surfaces (with fancy cut-outs)
  
• Gear-wheel generator --> Gear box

• My Own Projects of Current Interest:
• Klein's Quartic surface
• Parameterized Bell
• 3D Penrose Tiles
• More suggestions will be given throughout the course …
• Approach me with your own ideas as soon as possible

Introduction to SLIDE

• SLIDE originated as a toy rendering system for CS 184
• SLIDE lies between Mathematica / Matlab and traditional CAD tools (Solidworks, Autocad)
• It describes boundary representations (B-reps)
• Most numerical values can be substituted by expressions that are evaluated in each rendered frame.
• Offers interactive fine tuning of critical parameters via sliders
• It builds on OpenGl (for rendering) and Tcl (user interface, expression parsing)
• Main drawbacks:
• Not a properly maintained system.
• Tcl is a pain during the debugging process!
  

Some SLIDE and Tcl Basics

Next Homework Assignment:

Install SLIDE, and explore some of the demo files above.