CS 294-3: RAPID PROTOTYPING
Lecture #5 -- Sep. 29, 2000.

Discussion of Old Assignments

• Look at your symmetry demonstration parts.
  Symmetry of the green "Iggle" part.
• Comments on triangle approximation to sphere:
  How many triangles needed to make chord error less then 1% ?
  - - about 500

Discussion of: "Layered Manufacturing of Thin-Walled Parts"

• Regions on each layer that need to be solidified.
• Finding offset contours.
• Doing Boolean operations.

QuickSlice -- Advanced Modes

• Look at your panel designs.
• What did you learn about QuickSlice in your latest assignment?
  - - the fast-build option
  - - the cross-hatch option
  - - manual control of the roads on each layer
• See also Hints and Experiences in the Use of Quickslice.

Designing parts with SLIDE using Boolean set operations

• WHY: -- CSG is a very convenient way to describe certain geometries.
• Capabilities (and lack thereof) in SLIDE: CSG only between closed, watertight shells.
  - - This is a very clean conceptual model.
  - - Cannot visualize it in SLIDE in real time.
• Boolean operations will be carried out on a layer by layer basis -- after slicing.
  Here are the basic steps; for more details see below.
• See also the LSIF web page.

Entering the FDM Machine at the SSL Level

• The SSL format (You don't have to understand it !).
• Just open an SSL file from within QuickSlice,
  - - inspect the slices
  - - build supports (and a base)
  - - build roads (possibly modified to suit your needs)
  - - Save SML (then run the part with FDMsend)

Homework Assignment:

A#5: Design a Part with SLIDE using Booleans

• In a recent version of SLIDE, when you tried to render the boolean part (e.g., uPart) nothing appears in the viewing window -- even though it properly showed up in the SIF file when saved it in that form.
  BUT THIS HAS BEEN FIXED ! -- Thanks Jane !
  You now just need to specify the boolean groups.

  Here is a sample SLIDE file from which you can get started to do your own design.

• There were many problems with the "chsugrad" account, so we abandoned that one
  and set everything up for an account called "cs285" (same password).
  • ssh tiramisu.cs -l cs285
  • when prompted, type the password given out in class

• scp doesn't work from tiramisu
  So this is what you need to do:
  • On tiramisu:
    In the directory ~cs285/CS294/ make yourself your own working directory: "YOUR_DIR"
  • On your machine:
    scp test.sif cs285@tiramisu.cs:CS294/YOUR_DIR/
  • On tiramisu:
    /project/cs/sequin/caffe/sif/slicer/slicer.sgi -t 0.01 -of test.lsif -isif test.sif
    /project/cs/sequin/caffe/sif/lsif/glsif.sgi -o test.ssl -l ssl -t test.lsif
  • On your machine:
    scp cs285@tiramisu.cs:CS294/YOUR_DIR/test.ssl .
  • On tiramisu:
    Clean out the contents of your own working directory, YOUR_DIR, after you are done.
    -- Thanks for conserving disk space !

• The slicer program did not want to parse files with "^M" at the end of each line --
  BUT THIS HAS BEEN FIXED ! -- Thanks Sara !

  But if you ever need to remove these offending characters, here is what you can do:
  for instance, using the emacs editor on tiramisu:

  • setenv DISPLAY YOUR_MACHINE:0.0
  • emacs dirty.sif
  • Esc Shift-5
  • By click-dragging with mouse, copy a "^M" in to the "Query replace: " prompt line at the bottom and press Return
  • press Return again to indicate that you want to replace "^M" with ""
  • press Shift-1 to indicate that you want to change all occurrences -- and wait a while...
  • save modified file by typing Ctrl-x and Ctrl-s
  • quit emacs by typing Ctrl-x and Ctrl-c

Sorry for the inconvenience -- but this is life in a heterogeneous environment ...

You don't actually have to build your part
-- unless you have a neat design and you would like to see it.
Otherwise, it is sufficient to run your SSL files through QuickSlice,
and then inspect them to see whether you got what you expected.

Please hand in on Friday an ISO-plot of your collection of SSL curves
captured from the QuickSlice display window.