CSU540 Computer Graphics - Fall 2005 - Futrelle - Semester Programming Assignment #2 (SP2)

"Fancy Models" -- Professor Futrelle

DUE 11:59 PM, TUESDAY, NOVEMBER 22nd, 2005

Version of 15 November 2005

Building a scene using rectangles and sweeping

The assignment, SP2:

• The goal is to create a container, such as a vase or pot, with an interior that is visible. (The cross-section of a simple pot is shown at the end of this page.)


• In addition, you should attempt to place it in a simple scene. At a minimum, it could sit on the floor of a room with two walls behind it, as does the bottle in the 3D figure at the bottom of the page, from a student in my grad graphics class, a figure that I've shown you before.


• Beyond that, you could place your container on a table in the room.


• The one strategy in the model construction that goes slightly beyond the SP1 cone model is that when a line is swept (rotated) around an axis and neither endpoint is on the axis, then sweeping two points will produce two new points, a quadrilateral. You use the four points to create two triangles.


• I would suggest that you make a few measurements of a real pot or vase or similar container, to help add realism and to familiarize yourself with the process of modeling the real world.


• As before, creating your object around an axis, and at the origin is the way to proceed. Then translate it to its desired position.


• After your container is positioned, you can rotate the entire scene, walls, floor, and all (each wall and the floor is two triangles) to get an interesting view. Remember to set your ambient illumination level high enough so there's no part of the scene that goes completely dark.


• Making a table is relatively easy, once you have a routine that produces two triangles when passed four points. The table can be built at the origin too, right under your container. Legs can be rectangular solids too. If the legs are a bit difficult to do, create a simple thin table that can function as a "mat" under your container.


• Extra, extra credit! Put some flowers sticking out of your vase or growing in your pot. Green stems with colorful petals on the end, a few leaves. Would be super if anyone could pull this off by the end of the semester.

See also the list mail item here, which contains additional early notes on SP2.

SP2 uses techniques that are very similar to those in SP1. One difference is that when a portion of the contour such as the line BC is swept, it produces a rectangle, which should then be represented as two triangles. Portions of the contour that touch the rotation axis, such as AB and EF, produce triangles when rotated, since the point on the rotation axis remains fixed.

3D ray traced figure with a spiked bottle in a two-walled room:

Go to CSU540 home page. or RPF's Teaching Gateway or homepage