Skip to main content
Course web for the Spring 2019 Computer Graphics Class

Month: February 2019

Grading Problem

We accidentally posted Workbook 3 grades to the Workbook 2 assignment in Canvas.

Fortunately, we caught this right away.

Workbook 3 grades should now be posted correctly.

We have re-posted your Workbook 2 grade (hopefully correctly).

The only issue is that if you look at your Workbook 2 grade comments you will see your workbook 3 grade comments (and extra copies of the workbook 2 grade comments).

Workbook 2 Grading Questions

A few questions have come up with Workbook 2 grades:

  1. For page 5, exercise 1: The intent was that whenever a circle is under the mouse it should change color. The example solution does this. However, at least two people interpreted this as “if there is a click,” then change color. The graders did not consider this a correct answer. However, we can see how a student might read the assignment differently than we did. If you had this interpretation, and you believe that your code works correctly, and you lost the 1/2 point for not having circles change color, send a private message on Piazza and we will re-evaluate. Please do this before Friday 3/1.
  2. Students still seem confused about the bonus points. Please read We keep track of the bonus points you earned (they are listed at the end of the grading description), but they do not change your grade for this assignment. If you collect sufficient bonus points over the semester we will raise your overall workbooks score.

Mistake in Workbook 5

A student pointed out that in the original version of Workbook 5, what I said was a 5, 12, 13 triangle really was a 25,120, sqrt(25^2+120^2) triangle. Sorry about that. I have fixed it.

If you did your import after about 10pm on Monday, you will not see this problem – I have fixed it.

If you imported workbook 5 before about 10pm Monday, you will see this problem.

If you have the broken version you can:

1. either copy or pull a new version of 4-arclength.html and 4-arclength.js from

2. edit the files as follows:

change the line in 4-arclength.html so that the “arcex” canvas has height 140 (not 90)
change lines 102 and 103 in arclength.js to be 10+50 for y (instead of 10+25)
change lines 130 and 131 in arclength.js to be 10+50 for y (instead of 10+25)

(warning: there was initially a typo – it is 10+50 not 10+10).


3. just solve the problem for the shorter triangle.

The week in CS559: Week 6 Feb 25-Mar 1: Curves and 3D

This week we’ll finish talking about curves and move on to making pictures in 3D. Almost everything we learned in 2D will be useful in 3D.

Week 6 ( Mon, Feb 25 – Fri, Mar 1): Creating 3D Stuff

Mon, Feb 25: Workbook 05: 2D Shapes assigned
Tue, Feb 26: Lecture: Cubics and Bezier Curves
Thu, Feb 28: Lecture: 3D Overview / Three Programming
Fri, Mar 1: Workbook 05: 2D Shapes due

And remember, the exam is coming up soon. (March 12th). More information will be provided this week.