CS 285: SOLID MODELING, Spring 2002

Assignment #8 : Monogram Blocks

We want to create designs and prototypes of monogram cubes like those
that grace the cover of "Goedel Escher Bach ..." by Hofstatter.

You may use sweeps to construct the individual letters in your monogram
by extruding the basic shape of each letter in a rather bold font.
To make a "negative" monogram cube, subtract these letters, suitably oriented, from a cube.

To make a "positive" monogram cube, you subtract the complements of each letter
from a cube -- again in the proper orientation.

Scale the whole object to fit in a specified size.

Remember that SLIDE will not actually perform any Boolean operations !
It will just display all the components, and the Z-buffer can only do Unions.
So this design will challenge your visualizations skills, until somebody writes a CDA routine ... :-)

Applying the Slicing and Boolean Union Operators

Unfortunately, the code for these utilities runs currently only on SGI machines; it has not yet been ported to the NT environmnet. You will have to access such an SGI machine remotely and proceed as described below:

Output a .sif triangle file of your part scaled to the appropriate size in inches.
Login to viz.cs.berkeley.edu as chsugrad
Make a directory to work in:
% mkdir CS285/your_name
Move to this new directory:
% cd CS285/your_name
Transfer your foo.sif file to this account, e.g., using secure shell and ftp.
Start Menu-->Secure Shell-->ssh
and connect to viz.cs.berkeley.edu
Then transfer files by
Start Menu-->Secure Shell->ftp
There is a graphical user interface.
To resolve the booleans and make a solid .ssl part run:
% sif2ssl -l 0 foo.sif foo.ssl
To make a hollow version run:
% sif2ssl foo.sif foo_hollow.ssl
To check the results run qs (Quickslice) and load the .ssl file:
% qs

Example Files

What you will learn:

Making complicated objects from simpler shapes.
How to use Boolean operations in solid modeling.
How to reduce a 3D Boolean problem to many 2D Booleans.
How to make "thin-walled" objects.

DUE DATES:

Phase 1: CAD Design in SLIDE (send me SLF file):
DUE: Friday, 3/15, 6pm.

The First Solutions

Will all of these designs work ?? You may not really get what you hope for ... We will discuss this in class.

This one clearly works ! Congratulations Young!

Phase 2: Two SML Files ready for fab:
-- 1) A dense, solid object in a 1-inch cube;
-- 2) A loosely filled hollow object in a 2-inch cube.
(run the slicing and boolean scripts on the SGI machine):
DUE: Tuesday, 3/19, 6pm.

Phase 3: Actual fabrication of the two cubes;
DUE : Monday, 4/1, 9:10am, in class.

Some Fabricated Solutions

PREVIOUS < - - - - > CS 285 HOME < - - - - > CURRENT LECTURE < - - - - > NEXT

Page Editor: Carlo H. Séquin