Lab 2
Animated Sculpture
Due: Sunday, November 16th 2014, 11:59pm
This lab was modeled after the
assignment 2
of Stanfords "Introduction to Computer Graphics" class, which was offered in 2009.
- Individual Effort:
- No team participation is really encouraged in the case of the homeworks or the labs.
You're are not allowed to use any libraries or extra code except
gl-matrix, webgl-utils.js and some helper functions
in order to initialize WebGL / load shaders. Especially Three.js is not allowed! If you're not sure or want to use some library, ask the teaching assistants before.
- Late Submission:
- In general late submission is not encouraged/accepted unless
there is a very good reason.
You are encouraged to submit on time. We are on a tight schedule. Being late
for one lab could affect the time left for you to complete subsequent labs.
All labs are due at the midnight of the specified due date.
Late Submissions are possible, yet they will be penalized.
- One day late: 15% penalty
- Two days late: 30% penalty
- Three days late: 50% penalty
- Four or more days late: 100% penalty.
Objectives:
While Lab 1 was rather mechanic, with the aim to help you understand the issues of
transformations and their realization in WebGL, the goal of this lab is to be a bit
more creative as well as further improve your understanding of transformations You will do
so by building and animating a
kinetic sculpture.
Requirements:
We have set a few basic requirements for this assignment:
- Your sculpture must be composed of at least 10 shapes (they do not
have to be unique). These shapes can include basic primitives (like
spheres, cylinders, etc). More complex shapes could also be modeled
in a modeling program, such as the open source
Blender, and loaded into our program.
- Your sculpture must contain at least 4 levels of hierarchy.
- The animation should move at least two components (in two different hierarchies) of your sculpture.
It should also be physically motivated (that is, there are no magical,
free-flying shapes).
- Please take and attach a screenshot of your sculpture. Identify
your sculpture's first four levels of hierarchy.
Other than this, you're free to design your sculpture any way you like!
Here are some possible ideas to get you started:
Grading:
- (30%) You have a program that can read in a geometry file and displays it.
- (60%) Your program creates a sculpture, that meets most requirements.
- (80%) Your program creates a sculpture, that meets all requirements, but no animation.
- (100%) Your program creates a sculpture, that meets all requirements, including animation.
- (110%) Your program creates a sculpture, that meets all requirements, including animation
and we think your sculpture is amazingly cool.
Hints
While this lab is intentionally free-form, you might find some of these
hints helpful. However, there are many roads that lead to Rome, as they say!
- It is important, that you are trying to break down the lab into
smaller goals, that you have an idea about on how to achieve. It's
perhaps worthwhile to have a simple parser that reads in a scene description.
Alternatively,
you could create a gui for controlling the light source and camera.
- You should think on how to read in the geometry. A parser for this will
be unavoidable. It might be good to lean on
the OBJ file format. It is a very
common format. Many modeling packackes can read and write OBJ files. Plus,
they are rather simple to understand.
You could then start with these sample Models.
- Lastly, you need to specify your scene graph. It is a very simple one.
Basically you need to be able to read in a tree structure. Perhaps the simplest
way is to provide a list of (parent, child) pairs and their point of attachment.
Besides just having a static tree, you might also want to specify how parent/child
is interacting (rotation, translation, scaling?) and how "fast" this motion should be.
There really is no standard for this notation.
- If you'd like to take a screen shot, you could do this by reading out the OpenGL
framebuffer. For simple image formats consult the
Portable Pixmap format.
Submission
- Be sure to double check your final submission by unzipping it
in another directory on a computer in the PC LAB and testing it. (Especially for
last minute submissions.) A project that doesn't run will lose
more points than one that is one day late.
- Be sure to submit any comments or remarks in a 'readme.txt' file.
- Submit your files at cewebs.cs.univie.ac.at.
Grading Criteria
Grading the labs will be based on the following:
- 80%: Correctness and adherence to assignment specification.
- 10%: Readability and structure of code, use of comments, indentation, etc.
- 5%: Efficiency and speed (only an issue if its very inefficient)
- 5%: Adherence to lab procedures (submitting, naming conventions, etc)
Last modified: September 15, 2014
Michael Phillips /
michael dot phillips at univie DOT ac DOT at