What Is Rendering
By Justin Slick
If you're new to 3d, you might have wondered what exactly is
rendering?. To casual fans and folks who are new to 3D production,
the concept can initially seem as cryptic and unapproachable as
While the sophisticated math and science behind rendering is far
beyond the scope of this article, the process plays a crucial role
in the computer graphics development cycle. We won’t go into too
much depth here, but no discussion of the CG pipeline would be
complete without at least mentioning the tools and methods for
rendering 3D images.
Like Developing Film:
Rendering is the most technically complex aspect of 3D production,
but it can actually be understood quite easily in the context of an
analogy: Much like a film photographer must develop and print his
photos before they can be displayed, computer graphics professionals
are burdened a similar necessity.
When an artist is working on a 3D scene, the models he manipulates
are actually a mathematical representation of points and surfaces
(more specifically, vertices and polygons) in three-dimensional
The term rendering refers to the calculations performed by a 3D
software package’s render engine to translate the scene from a
mathematical approximation to a finalized 2D image. During the
process, the entire scene’s spatial, textural, and lighting
information are combined to determine the color value of each pixel
in the flattened image.
Two Types of Rendering:
There are two major types of rendering, their chief difference being
the speed at which images are computed and finalized.
Real-Time Rendering: Real-Time Rendering is used most prominently in
gaming and interactive graphics, where images must be computed from
3D information at an incredibly rapid pace.
Interactivity: Because it is impossible to predict exactly how a
player will interact with the game environment, images must be
rendered in “real-time” as the action unfolds.
Speed Matters: In order for motion to appear fluid, a minimum of 18
- 20 frames per second must be rendered to the screen. Anything less
than this and action will appear choppy.
The methods: Real-time rendering is drastically improved by
dedicated graphics hardware (GPUs), and by pre-compiling as much
information as possible. A great deal of a game environment’s
lighting information is pre-computed and “baked” directly into the
environment’s texture files to improve render speed.
Offline or Pre-Rendering: Offline rendering is used in situations
where speed is less of an issue, with calculations typically
performed using multi-core CPUs rather than dedicated graphics
Predictability: Offline rendering is seen most frequently in
animation and effects work where visual complexity and photorealism
are held to a much higher standard. Since there is no
unpredictability as to what will appear in each frame, large studios
have been known to dedicate up to 90 hours render time to individual
Photorealism: Because offline rendering occurs within an open ended
time-frame, higher levels of photorealism can be achieved than with
real-time rendering. Characters, environments, and their associated
textures and lights are typically allowed higher polygon counts, and
4k (or higher) resolution texture files.
There are three major computational techniques used for most
rendering. Each has its own set of advantages and disadvantages,
making all three viable options in certain situations.
Scanline (or rasterization): Scanline rendering is used when speed
is a necessity, which makes it the technique of choice for real-time
rendering and interactive graphics. Instead of rendering an image
pixel-by-pixel, scanline renderers compute on a polygon by polygon
basis. Scanline techniques used in conjunction with precomputed
(baked) lighting can achieve speeds of 60 frames per second or
better on a high-end graphics card.
Raytracing: In raytracing, for every pixel in the scene, one (or
more) ray(s) of light are traced from the camera to the nearest 3D
object. The light ray is then passed through a set number of
"bounces", which can include reflection or refraction depending on
the materials in the 3D scene. The color of each pixel is computed
algorithmically based on the light ray's interaction with objects in
its traced path. Raytracing is capable of greater photorealism than
scanline, but is exponentially slower.
Radiosity: Unlike raytracing, radiosity is calculated independent of
the camera, and is surface oriented rather than pixel-by-pixel. The
primary function of radiosity is to more accurately simulate surface
color by accounting for indirect illumination (bounced diffuse
light). Radiosity is typically characterized by soft graduated
shadows and color bleeding, where light from brightly colored
objects "bleeds" onto nearby surfaces.
In practice, radiosity and raytracing are often used in conjunction
with one another, using the advantages of each system to achieve
impressive levels of photorealism.
Although rendering relies on incredibly sophisticated calculations,
today’s software provides easy to understand parameters that make it
so an artist never needs to deal with the underlying mathematics. A
render engine is included with every major 3D software suite, and
most of them include material and lighting packages that make it
possible to achieve stunning levels of photorealism.
The two most common render engines:
Mental Ray – Packaged with Autodesk Maya. Mental Ray is incredibly
versatile, relatively fast, and probably the most competent renderer
for character images that need subsurface scattering. Mental ray
uses a combination of raytracing and "global illumination" (radiosity).
V-Ray – You typically see V-Ray used in conjunction with 3DS
Max—together the pair is absolutely unrivaled for architectural
visualization and environment rendering. Chief advantages of VRay
over it's competitor are its lighting tools and extensive materials
library for arch-viz.
This was just a brief overview the basics of what it means to render
an image. It's a technical subject, but can be quite interesting
when you really start to take a deeper look at some of the common
techniques. If you're interested in learning more, there's a lot of
good reading around the web, and we'll continue adding more in the
weeks to come. Be sure to subscribe to our newsletter to stay up to
Interview with Animator Willi Waizenegger
By Adrien-Luc Sanders
About Animation Guide: Tell us a little about who you are. Who do
you work for? What job do you do?
Willi: I do freelance 3D computer graphics and animation, with a
whole lot of multimedia thrown in to round things out. Although I've
worked for other people in the past, I'm primarily my own boss these
days. Originally, when I started out, I had plans on doing the usual
big-blockbuster animated features thing, but eventually found my own
My stuff tends to be more down-to-earth, not as "artsy," creating
animations and graphics for TV commercials, TV shows and other video
productions, as well as visualization stuff, such as in the medical
or architectural areas. A lot of my work ends up as elements in
print and web design, too. As a freelancer, I found it limiting to
make a freelance career out of just 3d animation, so I became an
expert on all sorts of multimedia skills. Flash animation, web
design, CD authoring, etc.--I find it extremely rewarding.
About Animation Guide: How long have you been working in the
Willi: That's an interesting question. The movie, "Tron" is as far
back as I can remember that I first considered getting involved with
3D. It just blew me away.
I first started actually dabbling with 3D in the early 90's with the
release of 3D Studio, Version 2 (before it became 3D Studio Max). A
friend of mine owned it and I got him sick and tired of me asking to
But, it was actually in the Spring of 2000 that I got a "real" job
as an animator, a month out of school, doing broadcast graphics. It
just snow-balled from there.
About Animation Guide: Name a few of the projects you've worked on
in the past.
Willi: Between my freelance work and my work for television
production facilities, that's really hard to say. I know I can
document over 900 television commercials, television shows and
infomercials that I've done graphics for (3D or otherwise). I've
also done print and web elements, as well as animations for
Besides animations, I've also created 3D virtual sets for
television, such as one I did for a show called "Power Play." This
show featured new and upcoming computer game releases, with the host
interviewing game programmers and such. The show took place in
space, in a space ship that looked very much like a game controller
(of course), which I modeled and animated in 3D. The interview set
was also done in 3D. Talent was shot in front of a green screen and
chroma-keyed into the room that I had built.
I loved doing that show. It was heavily 3D graphics oriented and
kept me really busy. It was filled with 3D rooms, animations,
bumpers, elements, etc.
Another project I did was a 5-animation contract for a
high-definition movie projector company for their company/product
demo reel. These animations were transitions between segments in the
demo and featured a roller coaster ride on top of movie film strips.
It was all done in high-def, which is the first time I played with
I could go on and on.
About Animation Guide: Do you have any future projects planned?
Willi: I have a bunch of things planned, mostly multimedia oriented,
but I do have a large-scale (30-foot X 35-foot) 3D print graphics
project in the works, for the educational department of a big
utility company. I'm also trying to develop a web-based interactive
3D world as my own pet project.
About Animation Guide: What prompted you to move into a career in
animation? How did you go about pursuing it?
Willi: Actually, I came by way of television. Behind-the-scenes
stuff such as television production, master control, stuff like
that. I loved doing the work, having spent almost twenty years doing
it. But, it started running its course with me. I found myself in a
rut. This was the late 1990's and by that time, I had fallen
completely in love with 3D graphics.
My wife suggested I go back to school full time for 3D animation and
we moved to South Florida (from New Jersey), where I attended art
school. Being a bit older than the other students, I worked really
hard to make myself stand out. At the time, I thought I needed to
graduate with as much talent as if I had been in the industry all
along, just to compete with everyone else. I probably tortured
myself a bit too much, but I loved the subject and it worked for me.
My wife was also earning the income for the two of us and I felt I
owed it to her to succeed.
When I graduated, I thought I was getting out of the television
racket, but a month later I got a job in...you guessed
it...television. This time in broadcast graphics. I loved the job
but in 2002, the lousy economy forced me to become a freelancer. The
rest is history.
About Animation Guide: What kind of education did it take to get you
where you are today? What's your alma mater?
Willi: I attended The Art Institute of Fort Lauderdale, which proved
to be a great school. Besides learning the software, I learned all
sorts of art skills, such as drawing, painting, composition,
photography, etc. It was a great well-rounded education and I met
some of the people I would network with for the rest of my career.
But, most of my learning was, and still is, from reading on my own.
All of the magazines I subscribed to were computer
graphics-oriented. I read, read, read, and then read some more on
I also made myself become a "student of life." I forced myself to
see the little details in everything, such as how people move, or
how that little stray strand of hair dances in a drafty room. The
way light and shadow hits the world around us or notice what color
water actually is.
About Animation Guide: What animation software packages do you
prefer to use? What would you recommend to a beginner?
Willi: There are so many really great software packages out there
that it's difficult to prefer one over the other. I'm partial to 3D
Studio Max, mostly because I've spent so much time on it that it's
become easy to me and I'm so busy that getting into another
program's learning curve is not possible right now.
3D Studio Max has also matured into one fantastic tool that does so
much really well. It's well suited for many different lines of work,
such as television, visualization, movie, print...the list goes on
and on. The best bang for the buck.
However, because most high-end packages require a big learning
curve, if I had to start from scratch, I think I would examine the
end result first and go from there. In other words, if you look
closely, each package has its own "look" that you can pick out if
you spend enough time around 3D. The look of the final render is
what I'm talking about.
Then, spend some time reading about each choice. Actually pick up
some manuals if you can, or spend some time sitting on the floor of
book stores reading. You can sometimes get a feel for how well you
mesh with a given package by doing that.
As for a 2D package, there's a lot to be said about Flash. I've used
it for broadcast projects as well as for the internet.
About Animation Guide: Apples or oranges, tea or coffee: do you
prefer traditional animation, or computer animation?
Willi: In the end, it's all about using the right tool for the job.
When working on a deadline (which is always), you have to assess
what will best get you the results you need. From time to time, it's
a combination of both.
For my personal stuff, I usually gravitate towards computer
animation. I love being able to save multiple versions, backtrack,
try new things, and have time to do it all. I've done both, and
enjoy both, but the nod goes to the keyboard.
Naturally, I'll plan things out with a pencil and paper first if I
About Animation Guide: Are you currently working on, or have you
worked on in the past, any independent animation projects? Tell us
Willi: I did a little 3-minute 3D animation project called "Pee-Pee
Stop" about a little alien traveling through space and having to
make a bathroom stop at an intergalactic rest area, and not having
an easy time of it.
About Animation Guide: Can you offer any advice to those interested
in producing their own independent animations?
Willi: Take your time, be open to different options, and don't be
afraid to bounce ideas off people you trust.
About Animation Guide: What about those just considering starting in
animation? Any educational or career advice, memorable lessons, etc?
Willi: Read, learn, look around you, draw, imagine, play "what if,"
and most of all...live and notice the little things. After all,
that's what you're trying to recreate. Even the untrained eye of the
casual audience can sense when something's not right with movement,
or the details are just not what they normally experience. It may
not be anything they can put their finger on, but it may translate
in them not liking the production for reasons they cannot explain.
So, pay attention to the details if the schedule allows.
From a professional point of view, remember that it's not as easy to
break into animation as some other professions (you can always fall
back on digging ditches or flipping burgers). It really is an
interesting way to make a living and there are a lot of new people
trying to get in all the time. You have to really make up your mind
that it's what you want to do and then work harder than you've ever
worked to make yourself stand out. Keep the end goal in mind at all
Look out for animation or modeling work that may be slightly
different than what you had in mind in the first place (unless
working for Pixar really is the only thing you want to do). Trust
me, animation is enjoyable no matter what the project is.
Try to track down a copy of "The Illusion of Life: Disney Animation"
by Ollie Johnston and Frank Thomas. It's considered one of the
bibles of 2d animation. I got a lot of mileage from my copy.
And last, but most important of all, keep in mind that it doesn't
matter if you're the most talented artist in the entire school, or
that you have the best equipment money can buy. You really are only
as good as your reputation says you are. It sounds corny, but it
boils down to making your client or boss look good to his/her client
or boss. Period.
About Animation Guide: Do you ever appear at conferences? What
animation events and conferences would you recommend?
Willi: Siggraph is the biggie in my book and a great place to
network, which I'm a fan of doing.
About Animation Guide: Can we find you in print or on the web?
Willi: I have a lot of my work featured on my website (www.williw.com).
Other than that, I've done a ton of web site and Flash creation,
which is all over the internet.
Besides video, a lot of my 3D work is featured in brochures and
posters, especially in trade shows where product demonstration comes
About Animation Guide: What, in your opinion, is the most important
thing for an (aspiring) animator to remember?
It's a challenging field to break into but it's not impossible.
Persistence and patience will get you a job where even a much more
talented, but impatient, artist will quit and get into selling real
About Animation Guide: Tell us your best story about working in the
animation industry. Willi: There is a well known condom manufacturer
that approached a video production company I used to work for to do
a small video project. The producer on this project had me create a
small--I think it was about 5 seconds--animation that would then
freeze and hold on the last frame.
This animation featured a condom, with eyes and a mouth, that went
from a slightly slouched position, to a...er...stand-at-attention-stance
(you get the picture). While this happened, "Condom Man," as I
called him, would smile really wide, happy and proud.
Well, it probably doesn't take too much imagination to realize
that"Condom Man" ended up on the cutting room floor.
What Is Rendering
''Where do architects and designers get their ideas?'' The answer, of
course, is mainly from other architects and designers, so is it mere
casuistry to distinguish between tradition and plagiarism?
A building is akin to dogma; it is insolent, like dogma. Whether or no it is
permanent, it claims permanence, like a dogma. People ask why we have no
typical architecture of the modern world, like impressionism in painting.
Surely it is obviously because we have not enough dogmas; we cannot bear to
see anything in the sky that is solid and enduring, anything in the sky that
does not change like the clouds of the sky.
Gilbert K. Chesterton
A doctor can bury his mistakes, but an architect can only advise his clients
to plant vines.
Frank Lloyd Wright
A modern, harmonic and lively architecture is the visible sign of an
A structure becomes architectural, and not sculptural, when its elements no
longer have their justification in nature.
Ah, to build, to build! That is the noblest art of all the arts. Painting
and sculpture are but images, are merely shadows cast by outward things on
stone or canvas, having in themselves no separate existence. Architecture,
existing in itself, and not in seeming a something it is not, surpasses them
as substance shadow.
Henry Wadsworth Longfellow
All architects want to live beyond their deaths.
All architecture is great architecture after sunset; perhaps architecture is
really a nocturnal art, like the art of fireworks.
Gilbert K. Chesterton
All fine architectural values are human vales, else not valuable.
Frank Lloyd Wright