COM4503: 3D Computer Graphics
Assignment 2 (60%): Making objects and scenes
look less pristine in Computer Graphics
Dr Steve Maddock
Deadline: 3pm, Tuesday 16 January, 2024
1. Introduction
Realism in computer graphics can be considered in many
ways. Examples include photorealism (e.g. can we
distinguish a rendered image from a real image?),
behaviour realism in a simulation (e.g. does that simulated
human movement look real? does that human skin behave
realistically?), interaction realism (e.g. does that object
behave correctly when dropped from a height? does that
material deform when compressed?) and functional
realism (e.g. is the functional behaviour clear irrespective
of how the scene is rendered, for example, can I repair my
appliance using those nonphotorealistically rendered
instructions?)
This assignment is concerned with a specific aspect of
photorealism: how to make rendered scenes look less
pristine. Look around you at the surfaces and objects in
your vicinity. You might see dusty and dirty surfaces,
scratches and dents on objects and parts of the scene that
look old through wear-and-tear. I’m sure you can think of
other examples. But how are such appearances created in
computer graphics renderings? The focus of this research
study is on the use of texture-mapping approaches to
achieve less pristine renderings.
Learning Outcomes
This assignment addresses the following module learning
outcomes:
• Identify and compare a range of techniques for
increasing the realism of rendered scenes;
• Summarise and appraise information on a specific
topic in computer graphics.
2. The report
Structure
• The report should start with a short introduction to the
general topic and your reasoning behind the report
structure.
• This should be followed by some further sections that
structure the parts of your report. It is your decision
what sections you will use to structure the report and
what the order of these sections should be.
• The report should finish with a short conclusions
section.
• The report must be illustrated as described in the next
section.
Illustrations
These are an important part of the report – they must be
integral to the discussion, not an afterthought. You will
lose marks if these illustrations are not included. Their
connectedness to the discussion will be considered in the
marking.
The following must be included:
• Screenshots from assignment 1: You must use at
least three screenshots from Assignment 1 to illustrate
your report. These should be examples where you
have made changes to your program from Assignment
1 to make the rendered scene look less pristine. For
example, using texture-mapping, you might add some
dirty marks to the alien’s clothing or you might use
diffuse and specular textures to make the security lamp
look rusty, etc. If you wish, you can also add an extra
object that has imperfections. You must decide what
changes to make. There should be at least three unique
changes. You should show before and after pictures
from making a change and you should also show the
texture maps that have been used and describe how
they have been used.
• Photographs of the real world: You must take three
photographs from the real world that show real-world
objects or scenes that look less pristine. These must be
used as illustrations in your report. You might also use
some extra photographs that show close-up views of
parts of your photographs, or, if the resolution is good
enough, you can just zoom in on parts of your
photographs. Try to take photographs that match some
parts of your scene from Assignment 1, e.g. some dirty
marks on clothing. This would then allow you to
contrast the real photograph with your simulated
version using texture maps.
• Illustrations using commercial software: You must
make at least three illustrations using commercial
software to illustrate techniques that can be used to
produce less pristine renderings. This will involve you
learning how to use free commercial software such as
Unity or Blender to do this – both these pieces of
software are free to students. These could be
renderings of example objects that look less pristine.
Your main text would then describe what techniques
are used in producing the less pristine rendering effect.
If the techniques improve on the examples used in
‘screenshots from assignment 1’ that gives you
something else to discuss.
• You can also use some general illustrations from my
lecture notes and from the Internet. However, you
must check the copyright permissions before you use
any illustrations from the Internet.
Things to consider
The following is a list of some of the things you might
consider in your report:
• At some point in your report, you might consider the
language and terminology you will use to refer to old,
worn, dirty, aged objects and scenes. What kinds of
imperfection might be considered? What does it mean
to be not pristine? What might cause something to be
not pristine? Misuse? Time? Interaction with other
objects? Some other reason? Is it important to consider
the cause of an effect? Put your personal, individual
ideas into this – what do you see when you look around
at indoor and outdoor spaces that you know?
• The focus of the research study is on texture-mapping
approaches that can be used in rendering less pristine
scenes. What can be achieved using texture-mapping
approaches and what cannot?
• An aspect you might consider is how to control the use
of techniques to produce non-pristine surfaces. For
example, how might you control the application of
imperfections? Is it a labour-intensive, manual process
or can it be automated in some way? This
consideration might include discussions of cause and
effect (can a program automatically add an
imperfection based on some interaction) and artistic
control (if a program decides the imperfection, is
artistic control lost?). Also, is time part of the
consideration, i.e. change in an imperfection over
time?
Decisions and skills
As part of the assignment, you will need to make decisions
about what should be presented, make decisions about the
ordering of information, decide what should be assumed
and what should be explained (you can assume I know
about my lecture notes – as an example, there is no need
to explain the detailed workings of any common texturing
approach covered in my lecture notes; a brief summary
using a diagram would suffice), link to reliable
information sources, and use appropriate language in your
report. You are finding, understanding, filtering,
organising and presenting information. You are
demonstrating that you can summarise and appraise
information about computer graphics.
References
I expect to see at least five published research papers in
your reference list, as well as other kinds of reference, e.g.
online materials that are reputable.
The following are a few published research papers you
might consider, the titles of which you can use to search
for more papers at Google Scholar
(https://scholar.google.com):
• Becket W, Badler NI. Imperfection for realistic image
synthesis. Journal of Visualization and Computer
Animation 1990;1(1):26–32
• Bellini, R., Kleiman, Y. and Cohen-Or, D., 2016.
Time-varying weathering in texture space. ACM
Transactions on Graphics (TOG), 35(4), pp.1-11.
• Mérillou, S. and Ghazanfarpour, D., 2008. A survey of
aging and weathering phenomena in computer
graphics. Computers & Graphics, 32(2), pp.159-174.
3. Deliverables
• The report should be 3000 words (+/- 10%). This total
does not include the list of references, the figure
captions or any appropriate tables of information. You
may include as many pictures as you deem
appropriate.
• You should submit the report via Blackboard as a pdf
document.
• You must include the following statement at the start
of the report:
/* I declare that this work is my own.
Author: < name >, < email address > */
4. Marking
The following aspects will be considered equally:
• Coverage of the topic area and relevance of material –
Is the material included relevant? Is there evidence of
independent reading to find advanced/interesting
information for the report? Are the references good?
• Knowledge and understanding of relevant material –
Do you demonstrate knowledge and understanding of
what you are writing about? Is deeper understanding
demonstrated by comparing and contrasting ideas? Is
your information accurate, or is some of the material
misleading or even incorrect, demonstrating that you
don’t understand it?
• Organisation, clarity of expression and illustrations –
Is the report tidy and organised, with a good flow of
information? Are all points in the writing expressed
clearly and succinctly, and supported with the use of
diagrams? Good use of illustrations. Are all the
requested illustrations included? All illustrations
should have a figure number and a caption and be
referred to from the main text.
5. Other
• Use of generative AI tools (e.g. ChatGPT): If you
make use of such tools, you must include an extra
Appendix to your report that describes exactly how the
tools have been used, including any prompts you used
with such systems. This Appendix does not count
towards the word count of the report. However, please
bear in mind what it says in the Department’s student
handbooks:
o UG: https://sites.google.com/sheffield.ac.uk/comu
ghandbook/your-study/assessment/generative-ai-
and-assessments
o PGT: https://sites.google.com/sheffield.ac.uk/com
pgtstudenthandbook/home/your-
study/assessment/generative-ai-and-assessment
• Standard lateness penalties will apply.
• Turnitin will be used to check for use of unfair means.
• See the Department’s student handbooks for more
detailed information on lateness penalties and unfair
means:
o UG: https://sites.google.com/sheffield.ac.uk/comu
ghandbook/your-study/assessment/
o PGT: https://sites.google.com/sheffield.ac.uk/com
pgtstudenthandbook/home/your-study/assessment/