Rendering History

Early 3D shapes were wire frame representations of geometric shapes and it was possible to see the back of the object as well as the front.  Several advances were made and several hidden surface algorithms created so that a solid object could be rendered and look authentic.  Algorithms were developed in the 1970’s too for display of curved surfaces and shading.

In 1978 Blinn did a simulation of wrinkled surfaces.

Whitted developed ray tracing in 1980 .

Goral, Torrance, Greenberg and Bataille developed radiosity in 1984.  They modelled the interaction of light between diffuse surfaces.

New solutions for improving the speed of rendering and the photorealism are constantly being developed

Ivan Sutherland

http://www.cc.gatech.edu/classes/cs6751_97_fall/projects/abowd_team/ivan/ivan.html

Ivan Sutherland is thought by many to be the creator of computer graphics. He wanted to make computers accessible for artists and draughtsmen.

His sketchpad was very important for the ideas that it introduced. It could be used to draw very precise drawings. It had a memory structure for storage and he used a lightpen, the predecessor of the mouse.

He later worked on integrated circuit design which helped lead to advanced chip design.   Now he is working on advanced hardware technology.

Display Technology

Application Programming Interface(API)
This is a technology that enables exchange of messages or data between two or more different software applications. It has been developed to allow two or more systems or components to exchange information that they can then use. It can also allow a certain amount of system modification to support data sharing between multiple applications. As this is developed it will lead to an open system of total cross platform consistency.

Open Graphics Library(OpenGL)
This defines a cross-language cross-platform API for writing applications producing 2D and 3D computer graphics. It is used to draw complex 3D scenes from simple primitives using it’s many function calls. It is widely used in animation across the market but Microsoft have developed and only use DirectX on their platforms. DirectX is more a hardware interface and is widely used in games.

OpenGL ES is a royalty-free, cross platform API used in consoles, phones, appliances and vehicles.

As display technology has developed so has the quality of the display hardware clunky computers to flat screen monitors.  The graphics have changed from blurry pictures to  crisp clear images.

Limitations of 3D

3D imagery has developed enormously over the past thirty years and today 3D is now much more realistic. Hardware and software has also progressed enormously so that it is much easier to put together sophisticated imagery and animation.

File Size
It is very easy when creating 3D imagery to create enormous files so that up to date computer/consoles with large high quality central processing units are a necessity. This can make the cost of hardware very expensive for film animation and 3D Games creation.

Image quality and poly counts The higher the poly count the more detailed will be the image and the fluidity of animation. Each image is made up of a number of polygons and the number used is called the poly count. A very high poly count in a scene will mean enormously large files leading to slowness and the game crashing. When downloading on a computer a high poly count takes longer to download. Various strategies are used to lower the poly count.

• Mapping (Basically putting a detailed surface on an object) is used to reduce the poly count.
• With small or distant objects, where a detailed image is not required, a low poly image is used.
• Copying images to reduce overall size is also used.A balance has to be struck between size and quality.

There are many 3D programs available, some more suitable than others for specific tasks. In producing 3D imagery in films or games it is usual for several different graphic software programs to be used which demands a high skill level in the workforce and an expensive workforce.

Computer Graphic Images

Computer Graphics Development
The full potential of computer graphics was realised in 1963 when Sunderland developed a system for man-made interactive pictures.The barriers to development were cost, the need for hardware and software development and it’s enormous complexity both for graphics and for systems. The cost of computer equipment has dropped year by year, operating systems were improved and new software keeps being developed. This has meant that computer graphics have been constantly improving.

History
In the 1960’s Csuri and John Whitney Senior were two of the major pioneers in computer graphic design. Csuri won an award for an animated film Hummingbird in 1966 and created Hummingbird II in 1969.

http://arts.osu.edu/3news_events/a_news/news_summer_2006/csuri_siggraph.html

He brought together graduate students to form a computer graphic research team in 1973 and in 1984 he established the Advanced Computing Centre for the Arts and Design. He was instrumental in encouraging the development of computer graphics.

http://arts.osu.edu/3news_events/a_news/news_summer_2006/csuri_siggraph.html

Wondrous Spring explored colour and light with photography and sculpture and was created by Csuri in 1992 showing how much computer graphics has developed and why Csuri is known as the father of digital art.

In the 1970’s there was the first use of 3D computer graphic images in films. animation was also improving during this time. 2d computer animation was used in Westworld and 3D vector graphics were used in Star Wars episode IV.

In the 1980’s ray tracings rendering was developed and there was a growth of digital graphics in advertising and in films. Two well known film series, using digital graphics at this time, were Star War films and Indiana Jones films. Particle systems animation was also being developed.

In the 1990’s and 2000’s continuing improvement was made. Two notable film series successes with 3D imagery were Harry Potter and Lord of the Rings. Full length computer generated films were also made including Toy Story 1995, A Bug’s Life 1998 and Antz 1998.

Games Development
As computer graphics and electronics developed so did the digital games industry with three major names emerging. These were with their most recent consoles:-Sony (X box 360), Nintendo(Wii) and Microsoft(Playstation 3). They brought out games consoles and games and continue in to bring out every year new games and less frequently improved consoles. Most money is expected to be made through software so this will encourage the continuing development of computer graphics and systems as the games industry moves into visual reality.

3D Software Available

3dsmax is a modelling/animation package widely used in industry , in films and on television. It allows you to build virtual objects, characters and environments on the computer. Surface colour and texture can then be added to surfaces and lighting added. You can then animate objects in the scene, adjust cameras and render scenes.

Many game development companies use this software. The necessity of fast playback time means that designers must play close attention to the amount of detail and 3dmax allows this.

It is also used to create film mattes. This is a background film image used behind live actors, who have been filmed on a green screen.

The widest use of 3dmax is for educational videos, TV commercials and short films.

3dsmax provides tools for character animation. The character studio plug-in takes over many tasks such as the creation of a skeleton and the basic walk cycle.
http://digitalmediaacademy.org/courses/computer-camp-3ds-max-III.html

It is also used by architects, engineers etc for visualisation, showing how machines or products work.

The Cult 3D utility enables for website viewers to rotate and view a 3dmax object over the internet.

Havok, also available as a 3dmax plug-in, allows real time interaction between objects and characters and is widely used in electronic games and in special effects in films.

Maya Used in “the Mummy”, this is an extremely powerful program, allowing complex animation and rendering linkages. it can be used with Windows, Linux and Macs. It also has a a nonlinear modelling history and Mental Ray rendering. this program has been much used in the film industry. It, like 3ds max, is also now owned by Autodesk. Maya has a painting facility which 3ds max does not have and is very good with nurbs.

An important feature of Maya is it’s openness to third party software. This makes it very popular with film studios who, using only the core, can write and add their own software to it using the provided software kit. The core of Maya is written in C++. The scripting language is MEL (Maya Embedded language) which also allows users to customise it’s functionality.

Autocad is used for 2D and 3D design and technical drawing. Additional tools allow it to be used by architects and engineers.

 

 

Inventor is used in design and engineering to create perfect new products.

Auto Visualise 3D is a 3d software visualisation program specially designed for biomedical imagery. It is used in microscopy, magnetic resonance imaging and x-ray computed tomography.

Cinema 4D, together with the plug-ins, is advanced 3D software. It offers advance radiosity, rendering and sophisticated character tools. It is very popular because of it’s BodyPaint 3D functionality.
http://www.maxon.net/pages/dyn files/dyn htx/htx/solmovie e.html
Camera mapping in Cinema 4D was used in about 150 shot in Narnia and in Spiderman it was used to create realistic digital environments. and repaint sky elements.


Blender is one of the best free 3d applications available with a full range of tools and functionality .
Lightwave 3D is a dual application featuring separate modeller/texturing and animation/lighting/rendering applications.
Bryce 3D is primarily a landscape-rendering application, designed to produce skies, seas and terrains.
Mojo World wants to take designers a step further than Bryce and instead of just creating a landscape it will create an entire planet.
Swift 3D is aimed at users wanting to produce high quality Flash animation
Rhino 3D is a popular nurbs modeller capable of designing jewellery or aircraft. It reads and writes in most industry standard 2D and 3D formats.
Vue 6 is best for creating natural real world scenes.

 

 

Mudbox is a brush-based sculpting software designed for digital sculptors.

 

Soft Image – Used in “Godzilla” This program combines inspiring modelling with nonlinear animation, scripting and rendering.

Ray Tracing

Ray tracing works on the principle that a light source sends out straight rays which continue on its path until it collides with an object. If the object is reflective like metal or transparent like glass, refraction is caused and the new path of the ray is dependent on the objects properties. The ray continues until it hits a new object and the pattern is repeated. Refraction is the bending of the path of a light wave as it passes across the boundary separating two media.

Ray tracing follows the path of a ray backwards, from the eye to the image and then to the light source.
http://www.geocities.com/jamisbuck/raytracing.html#Shadows
The illustration below shows how ray tracing deals with shadows.

http://www.geocities.com/jamisbuck/raytracing.html#Shadows

Ray tracing doesn’t take account of diffuse interreflections.

This rendering technique needs a huge amount of processing power, as each time the camera moves, new calculations must be made about the lighting and the time required to produce an image is hugely affected by the number of light sources.

Radiosity

Surfaces are illuminated by light whether by direct light from a light source or by reflected light from one or more surfaces in the environment. Smoke , fog or dust may inhibit the light. Different surfaces have a different reflectivity as some light is absorbed by the surface and some may pass through the surface. The reflectivity of a surface is often defined as its colour. The reflection of light energy in an environment causes “colour bleeding”, where a bright colour will “bleed”onto adjacent surfaces.

With Radiosity, computer image generation assumes surfaces are emitting and reflecting indirect uniform diffuse lighting over their whole area. It assumes all the energy is used in absorption and reflection and that it is viewpoint independent of the image. It also assumes that surfaces inter-reflect i.e. they both receive and send out light energy. To calculate radiosity, surfaces are broken down into patches.  Once a solution has been calculated, the camera can move around anywhere with this solution.  If however the light changes, a new solution has to be calculated.  The Radiosity of a surface is the rate at which energy leaves the surface, including energy reflected from other surfaces.

Radiosity gives colour subtlety.  Within 3Dmax there are working tools (e.g. exposure) to make a scene more realistic.

As seen fron the above images standard lighting, which is direct illumination,  has no reflected light and gives hard , blocky images and dark shadows.  It is however cheaper and faster to render so may be suitable for certain scenes.

Charles Csuri

 

Charles Csuri was known as the father of computer graphics. In 1964 he experimented with computer graphics technology and the following year he started making computer graphic films.
His research into computer animation and graphics has won him international reknown. With support from the National Science Foundation, the Navy and the Air force Office Scientific research, over 22 years he directed research into computer graphics with computer science graduates.
The results of this research have been widely used e.g. in flight simulators,computer-aided design, magnetic resonance imaging,architecture and special effects. Many well known animation films, like Star Wars and Toy Story, have had graduates from his program working on them.

Cartesian Co-ordinate System

Cartesian Co-ordinate System 

3D software packages use the Cartesian Co-ordinate System to create the illusion of working in three-dimensional space

This system was created by French Mathematician Rene Descartes in 1637 to try to merge algebra and Euclidean Geometry.  It has had an important role in analytical geometry, calculus and cartography.

The two axes that commonly define the 2-dimensional Cartesian system are x and y.

The point where the two axes meet is known as the origin (0,0)

 Early in the19th Century the z axis was added. It is known as the depth axis.  With this third axis it is possible to identify any point in a three-dimensional space.

A point 59 units along the negative x axis, 100 units along the positive y axis and 50 units along the negative z axis, using the formula (x,y,z) would be written

(-59,100,-50)

The purpose of viewports is to be able to view a 3-dimensional object from different angles at the same time.  An orthographic view displays only two axes at a time and in the viewports the top, left and front viewports all show orthographic views.  Perspective shows a three- dimensional view.