CS 285: SOLID MODELING

Lecture #17 -- Mo, Apr. 1, 2002.

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Preparation

READ: Paper Scheduled for Discussion: "Gears" -- HANDOUT !

Progress on Monogram Cube Designs

What approaches did you end up taking ?
Question/problems with Phase_2 ?
Any problems with the Boolean operations ?

Wrap-up on the Prototypes of the Snap-together Tiles

Computer graphics --vs.-- Model making --vs.-- Functional prototyping --vs.-- Mass production:
It gets progressively harder, since ever more constraints apply !
Constraints on (inexpensive) injection-molded parts:
Shape must decompose into two half-shells that are pure height fields;
these shapes must be machineable themselves.

Introduction to Gears (follow handout)

Spur gears -- based on rolling cylinders.
Nomenclature of spur gears.
Definition of the tooth shape, based on involute.
Rack and pinion; internal gears.
Bevel gears -- based on rolling cones.
Use of plane of action (perpendicular to line where conre touch), and construction of back-cone for defining the shapes of the teeth.
Worm gear -- the two axes are skewed (offset from each other).
Hyperbolic gears -- for most general case of skewed axes.
Moebius gear -- computer graphics animation only.

Homework Assignments:

A#8: Monogram Blocks

Phase 1: CAD Design in SLIDE (send me slf file); DUE: Friday, 3/15, 6pm.
Phase 2: SML Files ready for fab (run the slicing and boolean scripts); DUE : Tuesday, 3/19, 6pm.
Phase 3: Actual fabrication of the two cubes; DUE : Monday, 4/1, 9:10am, in class.

Also complete your final prototype versions of your "polymorph" tiles: DUE : Monday, 4/1, 9:10am, in class.

Assignment #9:

Modify an existing SLIDE gear demonstration program to make two interlocking operational bevelled/conic gear wheels.
DUE : Wednesday, 4/3, ready to demonstrate in class.