CS 285: SOLID MODELING

Lecture #26 -- Monday, Nov. 28, 2011

Warm-up Thinking Exercise:

Assuming you had no access to the software described in the paper below,
and wanted to build a smooth 4"-diameter FDM sphere,
-- what approach would you take ?

How could you produce a narrow crooked tunnel through a solid block of FDM material
-- assuming it is not possible to remove any support from that tunnel ?

Paper Presentation by:   Sushrut Pavanaskar

• We want to build parts on the FDM machine from a (natural) CSG description.
• Doing clean Boolean operations in 3D is difficult.
• Doing clean offset surfaces in 3D is very difficult.
  -- How would YOU do that ?
• Since layered manufacturing works in 2D layers, we can defer these two difficult operations to the individual planes.

Address the following points:

1. How do 2D Booleans implement the 3D Boolean operation?
2. How do 2D offset contours implement 3D offset surfaces?
3. How does this relate to making thin-walled parts?
4. Which are the "tricky" areas of making a thin walled part with layered manufacturing?
5. How does this relate to the QuickSlice "Fast"-option?
6. How are the contour offsets generated?
7. What is the role of the Voronoi mountain?

Future Paper Presentations . . . 

Ongoing Assignments:  Work on your projects!