CS 284: CAGD
Lecture #18 -- Th 10/26, 2006.

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Preparation: -- BR'92: "The Surface Evolver" K. Brakke - skip Sections 3.4, 3.5, 4.2, 4.8, 5.4, 5.5, 6.2, 6.7, 9, 10.

First Paper Presentation by Ian Sammis

The whole, uninterrupted presentation for one paper should last between 20 and 25 minutes.

there may be interruptions due to questions, but "the clock will be stopped.".

Everybody in the class should read the papers carefully before the day that they are presented in class.
The class should be prepared to help the presenters with constructive and insightful questions and comments.
The presenters should be prepared to answer such questions.
The presentations will be judged for:

Organization of the material
Clarity of explanations
Quality of visual materials
Forcefulness and enthusiasm of oral presentation

Occasionally I may ask you to answer some questions on-line about the paper before coming to class.
I reserve the right to start a class with a short 10 minute pop quiz about the paper(s) for that day.

How you will be using the Evolver program to find a minimum energy shape for your genus-L surface.

Describe surface in terms of triangles or quadrilaterals.
Model only one fundamental domain -- bounded by "mirrors" to guarantee continuity.
Experiment with different steps of mesh clean-up, refinement, and optimization.

Start preparing for the 5-minute formal Project Proposal Presentations on November 2.
("Venture Capitalist Rally" -- How to get the "gold".)

Format:

Should last 4-5 minutes (hard 5 minute cutoff).
Start with an attention-grabber.
Be enthusiastic, make an impact.
Your peers will rank-order your performance.

Content:

The goal of the project
The approach you will take
The deliverables and demos resulting
Why this is a "good" project (somewhat of a "selling" job):

how useful it might be, or
just how "cool" it is going to be, or
what you hope to learn with this project ...

Check list and rating sheet:

Tonight, midnight: Due: Definitive 1-page project proposals (e-mail)!

Reading Assignment:

BS'92 "Minimizing the Squared Mean Curvature Integral …" Hsu et al
MC'87 "Marching Cubes ...". Lorensen and Cline

Current Homework Assignment: Make a genus-L Surface with D_Lh Symmetry (Phase 1)

Generate a rough polyhedral surface of genus-L, where L is the number of letters in your first name.
The surface should have D_Lh symmetry; i.e. L-fold rotational symmetry around the z-axis, as well as
mirror symmetry across the x-y-plane and across L planes that comprise the z-axis.
Build only the fundamental domain of this surface; i.e. 1 / 4L of the total object.
Keep it as simple as possible; i.e. use only 3-5 quadrilaterals or about twice as many triangles.
This piece of polyhedral surface then get's suitably mirrored and replicated to form the whole closed, watertight genus-L surface.
Start from the basic set-up in GenusL_SymmDLh.slf
All you have to do in this file is: replace the two place-holder quadrilaterals and adjust the replication number in the final surface assembly.
In the next phase of the assignment we will then convert this surface piece into the format of Brakke's Surface Evolver and experiment with it.
The goal is to find the surface of lowest bending energy while maintaining the specified genus and symmetries.

DUE: Tuesday, October 31, 2:10pm.

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Page Editor: Carlo H. Séquin

CS 284: CAGD Lecture #18 -- Th 10/26, 2006.