CS 285: SOLID MODELING

Lecture #5 -- We, Feb 2, 2000.

Preparation:

Procedural Shape Generation with SLIDE

• Discussion of your homework.
  Difficulties encountered in modeling a mug or teapot.
• Continued discussion of the SLIDE system

and how to use it to create elaborate shapes.

The Bare Essentials about Splines, Subdivision Surfaces

Bezier curve segments and their combination into C1-continuous curves.

A bezier segment interpolates its two end-point and approximates all other control points.
It is most useful to make short curved connections between known end points with known tangent directions.
Such edges can then readily be used as the edges for Bezier patches of the same order, using the same control points.

B-Splines, open and closed (periodic).

B-splines interpolate all control points; subsequent segments are defined by overlapping sets of control points.
B-splines can make nice smooth curves of arbitrary length and complexity with a guaranteed degree of continuity.
Cubic B-splines can give C2-continuity.
Smoothly closed curves can easily be constructed by repeating (order-1) control points in a cyclic manner;
need to specify (control_points + order)-number of knots ( 0, 1, 2, ...  cp+ord-1 ).

Basic Subdivision Surfaces (later)

Most useful to make water-tight shells of arbitrary genus with good continuity.
Advanced systems can provide varying degrees of smoothing and sharp edges as well.

Introduction to QuickSlice

The software for the Fused-Deposition Modeling (FDM) machine to cut the given geometrical shape in thin horizontal slices which will then be deposited, layer after layer, on top of each other. The software also generates the auxiliary support structure needed to support overhangs.

New and Ongoing Homework Assignment:

A#2: Get familiar with SLIDE -- and QuickSlice