What is a visual effect?
A visual effect is simply a computer generated effect that is blended with a movie, or animation to create an illusion of reality. For example, if we have a video of cloudy sky then we can create some lightning using VFX and blend it with our video of sky so that when people see it they got the feeling that it is actually lightning.
Where is it used?
You probably know where these visual effects are most needed and used. Yes, movies, television , and other entertainment media use VFX to create amazing visuals. But VFX is not just restricted to simple effects. You have seen lot of visual effects in Video editing and 3D creating sotwares. These effects are just a version of VFX. There are a lot of versions for VFX. The most dominant one is CGI or Computer Generated Imaginary. These are images created using computers. CGI is widely used in movies and games to create stunning backgrounds and life like characters. So you might have seen lot of CGI in your life while watching movies or playing games. These images are so inevitable to the entertainment industry that CGI is a multibillion dollar industry now. The availability of powerful computers and programs played an important role in popularizing CGI.
CGI and Hollywood.
CGI is widely used in Hollywood movies. So the history of CGI in one way or the other is also the story of Hollywood. The Hollywood movies especially scifi movies are a peice of wonder. Every movie will have at least one new visual effect you have never seen in your life. You go to the theaters not just to watch spiderman climbing the walls of buildings or the titanic sinking into the sea but also to enjoy the beauty of those buildings and effects that are purely CGI.
The first Hollywood movie that used CGI is "West World" released in 1973. It used 2D based CGI images to create visual illusion. Interestingly the second part of West World called as "Future World" is the first movie to use 3D based CGI images. This was just a beginning. The real VFX revolution is just about to start. The first movie that through which VFX became a buzz in Hollywood is the movie "Star Wars". It is released in 1977 and it introduced new trends in Hollywood. Then came a lot of movies that used CGI. But the movie that "rejuvenated" VFX was "Terminator 2-Judgment Day". It was a tremendous success, not because it is a fantastic movie but also it has lot of stunning visual effects. You probably might not forgot some of those effects. One of the unforgettable effect is the liquid metal and morphing effect that we meet through the villain T-1000.
The second movie that worth mentioning is Jurassic Park. After viewing the movie many think that the Dinosaurs used in that movie where real and they want those animals to be immediatly added to the National Zoo. Those dinosaurs where computer generated even though they look life like. They are animated and perfectly blend to the movie so that even a person with a doctorate in the study of dinosaurs think that they even exist now. Another movie that utilized the amazing potential of VFX is Titanic. There is no doubt that without those special effects the movie won't be so attractive and touching. More and more movies are added to the list that owe a huge part of their success to the VFX used in those movies. In short VFX has become an integral part of Hollywood.
Composting
The process of combining two or more images to a shot is called Composting. Composting is most commonly used to combine 3D images.It is not as simple as you think. When you do this the output must look real. Otherwise there is no meaning in composting. There are different techniques used in compositing. The most common are Bluescreen, Rotoscopy etc. Let us understand the most common compositing techinques in detail.
Rotoscopy:
Rotoscopy is a technique used in composting. It is an effective way of composting images. The first step in Rotoscopy is to project recorded live action film images to a frosted glass panel and then an outline is drawn around the objects. The device used to project images is called Rotoscope and hence the name Rotoscopy. The perfection in Rotoscopy based compositing depends on how sharp is the outlines drawn around objects to be included in the scene. Then computer generated images are carefully added to the background of these objects. The process of Rotoscopy is time consuming and need a lot of patience and talent to draw perfect outlines around objects because this ultimately affect the output scene. Rotoscopy is used perfectly in Star wars. The glowing wand in the hand of the hero is rotoscoped. The "actual" wand in his hand is covered with blue screen mat and a glowing wand is added to its place, which is CGI generated, using Rotoscopy.
Optical Printer:
Another technique used in compositing is Optical Printer. An optical printer has two projector heads. The important parts of an optical printer include film rate, lenses, camera finder, and adjustable shuttle controller. It is used to give visual effects like fade in fade out, slow motion etc to a movie scene. A combination of these effects can be added to a scene using Optical printers. They are widely used in the early stages of VFX, but now they are completely out of picture.
Match Moving:
The process of merging virtual objects to the footage of a already shot action movie is called Match Moving. Match Moving is a complex process that needs lot of precision and care. Match moving is entirely different from motion capturing where motion sensors to capture motion and blend it to the object to be animated. Here no motion sensors are used. Instead it is done just using movie camera. Match Moving is done by tracking the movement of the camera. This information is used to change the position of virtual camera inside the computer. It can be used to naturally blend the virtual with real scene in a movie. Match Moving is done using two popular software packages, Shake and Adobe After Effects.
Bluescreen:
Bluescreen are considered the basic element needed to create a visual effect. It acts as the backbone of VFX. Bluescreen is used to blend images to the background of a charecter. We can say that there is no VFX if there is no Bluescreen.
A blue or a green screen is placed behind the character. A character acts standing in front of this screen.The scene is shooted and the background is removed while editing. Now the scene is left with only the acting charecter. The background is rephotographed through a bluefilter to display just the background. A special kind of film is used to rephotograph the background to get a black&white negative film. The output will be a black&white image with the character at the middle of the background. This is called female mate.The background image is again rephotographed. The difference is that it is rephotographed using green and red filters instead of bluefilter. By doing this we get only the foreground image. This is called a male mate.
The background image is again rephotographed using male mate and the bluescreen shot is rephotographed using female mate. An optical printer is used to merge these two images into a single frame. But instead of optical printer we now use computer softwares to merge images into a single frame. Using softwares we will be able to give more charm and precision to each frame. We can also add different effects to these frames.
Motion Capturing:
The technology used to give life like movements to animated characters is called motion capturing. It is used in Hollywood movies, games,and cartoons to give realistic movements to CGI images.You might have been stunned and wowed when you see the war scenes in Lord of the Rings. Motion capturing is used to give life like movements to these charecters. In motion capturing sensors are used to record the movements of human beings and after that these movements are then given to 3D charecters. This is called Motion Capturing. With motion capturing you can create stunning animations. In motion capturing a man wears a suit fitted with complex sensors. These sensors are connected to a computer. The computer can read his motion with the help of these sensors and are digitally recorded. Then these motion files are imported to 3D softwares like 3D Max and these effects are applied to previously marked portions of a 3D image.
Motion capturing is the most effective way of giving life like movements to animated 3D characters. There are so many reasons for it. You can easily animate a 3D charecter. You can make him walk, dance, talk, or sit anything. But there are different "expressions" that you cannot easily create while animating. Facial expressions are one aspect. To create a natural facial effect for a 3D character is time consuming. Motion capturing can make this task easy. Facial motion capturing is used to do this. You might have seen the movie King Kong. The charecter touched our hearts. It is almost real and it fascinated us for a few days even after watching the movie. The character is not real, it is a 3D animated character and what makes it so real is its facial animation. These facial effects are done using facial motion capturing. Small sensors are placed at the face especially around the eyes and the lips to capture the facial effects of a humanbeing and then the captured motion is applied to the 3D character. It is the most complex form of motion capturing. Hundreds of sensors are fixed to the face of a man. Different filters are used in this kind of motion capturing. Marker tracker and markerless tracker are used to capture facial movements. High resolution cameras are used to track the facial movement of each marker fixed to the man's face. There are different marker technologies used in motion capturing. LED marker technology is widely used for real time motion capturing. Motionless trackers are used to track even the slightest movement of eyes and lips.
How it works?
Each and every movement of the actor can be recorded using high resolution motion camera. In motion capturing only his body movements are recorded and not his body.
Also the position of the camera is recorded while capturing the movements. This is to identify the camera angles to be given to the characters generated using computers. These data comprise a motion capture file and it is saved. Then this file is imported to a software like 3D Max and the motion is applied to the appropriate areas in the 3D objects. Thus a perfect animated effect is created.
The Matrix Revolution
While talking about VFX it is a must that we should mention atleast a words about Matrix. Matrix revolutionized the way people think about VFX. There are a lot of criticism about the way visual effects are used in the movie. But definitely a large percentage of those comments were of appreciation. The effects in Matrix really stunned the viewers. The viewers are taken to a world of magical realism from where they cannot come out for some time. Matrix showed the power of VFX and the extend to which we can use it in a movie.
Matrix is considered as a classical example of using VFX in movies. Every scene in Matrix introduced new effects which are a pleasure to watch. These effects are the stepping stones to new vistas in the world of VFX. So when we talk about the effects in Matrix then we have to talk about each and everyone of them. But the most perfect and innovative one is Bullet time. It is a new effect in which the camera rotates in a 360 degree angle around the charecters in Matrix. This effect required the skillful and creative use of computer to control the movement of a camera. Bullet time can be used to create scenes with slower rates of motion than the Slow motion technology.
The process of creating this effect is a very complex one. At first an array of still cameras are placed around the object to which we want to give Bullet motion. Then a sequence of pictures of the object is taken using these still cameras. These pictures are taken from different angles. Then these images are arranged in the correct order one after the other. These still images are used to create the illusion that the camera is rotating around the characters.
While the camera is moving around the object, we also got the feeling that the object is also moving. In matrix the camera path is set as visualized by computer. A laser targeting system is used for this purpose. The cameras in the array are aligned using this system. The system controls the movement of cameras, which automatically skipped the control to each camera in the array periodically. Using this technique the shots are taken sequentially according to the movement of the viewpoint. Then the frames are scanned by the computer for processing. This kind of innovative technologies and a lot of creativity and hard work is behind the creation of each effect in Matrix. That is why it is said to be a classic in the world of VFX.
A green screen is used as the background of object to which Bullet motion is to be applied. This is used to give screen effect to the shot. The motion rate of Bullet motion can thus be effectively controlled to give more clarity to the shot. One difficult problem here is slow rates of motion which is much slower than what is needed. To rectify this softwares are used to increase and maintain a constant motion rate.Then background images are blended to the background of the image.
Morphing
Morphing is the technique of transforming one object to another. The first movie that used morphing effects was "Willo". It used a effect in which the face of a man is transformed into an animal. The potential of morphing was understood by the entertainment industry and a lot of morphing effects are created and used in lot of movies and animations from there on.`
The movie that took morphing effects to a new height was Terminator 2 -Judgment Day. The movie is full of visual effects and the morphing effects used in it were outstanding and will be remembered for ever. If you see that movie then you will be a little bit surprised about how the villain in that movie easily transforms his shape. And probably you also think for a moment that if you have that skill.Morphing effects are skillfully and efficiently used in Terminator to animate the villain character. He can easily transform his hand into a sword and all. These effects are created using different morphing techniques.
In earlier days cross fading is used instead of morphing. It can be considered as an early form of morphing. With the invention of morphing cross fading is discarded. Morphing makes the creation of morph effects easy. There are a lot of morphing softwares you can use to create morphing effects. Using these softwares you can create stunting morphing effects. To do morphing we need two objects, one is the object to be morphed and other is the object to be obtained after morphing. Points are marked on the key areas of the two objects. It is these areas that transform into the morphed shape giving us an impression that the object have changed into another object. There are lot of softwares using which you can easily do animations. One such popular software used in movie production is Avid Elastic Reality System. There are a number of free morphing tools that you can use at your home computer too. One such free morphing tool is WinMorph.
The world of Dinosaurs.
You might have been astonished after seeing the dinosaurs of the Jurassic period in silver screen and thought how these dinosaurs are created. The way the dinosaurs move, eat, act, etc are so realistic that we actually fell in love with them. Jurassic park is a movie that explored the potential of using computers and VFX. The dinosaurs in that movie are not just created using CGI. It also used another technique called animatronics, which can be considered as a combination of animation and electronics. The models of these huge dinosaurs are created using appropriate materials and then are moved using a animatronics device. The technicians that handle these animatronics devices are called as puppetries. The first thing that the puppetries do is to understand the model to be animated very well. Then only these models can be efficiently animated because different models need different areas of the body to be animated in a particular manner. A dinosaur never walks like a man. So understanding the model gives an idea about how to move the object perfectly and naturally. Then puppetries give motion to these models. For example to move the hand of a dinosaur the puppetry have to move his hand to which a telemetric device is attached. So when the puppetry moves his hands this device informs the circuit controlling the dinosaur. Radio Frequency circuits are used to control the models. The process of creating the models is tedious and also time consuming. The main difference between animatronics and motion capturing is that the models to be animated are not CGI generated.
The world of 3D Graphics.
3D Graphics is a word that does not need any special introduction. Even if you did not know anything about 3D Graphics you might have seen a lot of 3D movies and animations. 3D graphics is mainly used in computer games. You might have played at least a single 3D game in your life. 3D characters and scenes are a hot commodity in the world of games. A game is rated not just based on the ease of play or the game intelligence but also of its stunning graphics.
First to create a 3D movie or a game we have to create a 3D environment.Creating a 3D character might be easy when compared to the effort needed to create a 3D world. Then we have to decide the way it is to be displayed in the screen. Which portion of it will we see at a point of time, which portion to hide, the position and arrangement of pixels in the screen etc.
Then only we can create a nice 3D environment. Lot of things need to be taken care of while creating 3D graphics. The first thing we should understand is we are creating a artificial world, they are created using softwares and the process of creating the 3D environment needs a lot of care, patience, and creativity. You see only a portion of the 3D world created for a game at a particular time. It depends on the way in which the 3D scene is defined and viewed. The potential of 3D is so wide that there is virtually no limit for the kind of environments, or characters or effects you can create with it. All you need are some powerful 3D creating and animating tools and some creativity. You can create stunning and great looking charecters and animations.
A 3D object is composed of different image components. It is based on these components that the quality of the 3D object is decided. The most important components of a 3D image include textures, lightning, perspective, depth etc. A 3D object also is formed by combining different 3D shapes like rectangles, squares, circles, lines, curves etc. To create a shape the first step is to create a wireframe which is a combination of thousands of such shapes. The next step is to give a surface for this wireframe.
Surface Texture:
A 3D surface has different properties. The information about a 3D surface depends on these properties.The surface of a image has the following properties:
Color: The image surface has a color.What is the color of the image, its distribution on the surface of the image, etc are determined by this property.
Texture: The smoothness of the image can be determined by this property.
Reflectance: It determines the amount of light being reflected, its intensity etc.
These are the three important properties that can be used to create a life like character. It is these properties are to be most importantly taken care of while creating a 3D image.
Lightning:
The realistic display of a 3D image requires the removal of lines and surfaces which are not visible from a particular viewpoint. To obtain this we must use the correct lightning effects on the surface of the object. The amount of light reflected, its depth etc plays an important role in defining the "originality" of a 3D object. A very useful but computationally intensive technique called Ray Tracing is used for this purpose. It plays an important role in determining the quality of the rendered image. Light falls on an object from different angles. It then reflects from the surface which create some sort of "shadow effects" and these effects play an important role in determining the quality of the 3D object rendered. It gives us an ideas about the strength, depth etc of the object. Different objects reflect light in a different manner. So special care and skill is needed while creating lightning effects.
Perspective
Perspective can be defined as the angle of view. It is a kind of transformation. It
gives us the feeling that an object in a scene is concentrated on a single point away
from the object. Most common type is one point perspective where the object seems
to be moving concentrated on a single point. There are also other kind of perspectives like two-point, three-point perspectives.
Depth
The depth plays an important role in creating the illusion that the object viewed is
real. To create this different kind of optical effects are used. One such effect is depth
of field. There are different depth of field like shallow depth of field, deep depth of
field etc.
Frame Rate
Frame Rate plays an important role in determining the quality of your animation.
Animators often try to give appropriate frame rates to their animations to make then
look natural. The number of frames per second is high for some animation while it
requires only 21-30 frames for some other animations. It depends on the kind of
scene you want to animate. To animate a man walking 21 or a bit higher frame rate
can be used. If you want to create a man running then you have to use a higher frame rate. In most 3D games to give originality to their animation animators and
programmers try to include 50-60 frames per second. This is to overcome the blurring between frames.
Camera Effects
The 3D objects are often given camera effects. This is also done to give more
originality to the animation. We can view a object from any angle in a 3D environment. This is done using virtual cameras. A virtual camera is not a real camera. You might
have used a "miniature" version of these "virtual cameras' in games with which you
can view a 3D object from different angles. A virtual camera can be used to view
objects from an angle you like. It is implemented in most 3D graphics creating
programs. The rendered image depends on the angle on which you have placed the
camera in the 3 dimensional area while creating the objects. You can use this camera to give different effects like field of visual ratio, zooming, rotating, dolly etc.
The virtual camera in a 3D software allows you to give different effect to your 3D
object. You can view the object from different angle. What you have to do is to just
click on the camera icon and drag the mouse to get a particular angle of vision. You
can give different camera effects to different frames in a 3D movie. What you have to
do is to create key frames and then apply different camera effects to these key frames.In this way you can create and shoot your own "virtual movie" in a computer.
Rendering
Rendering is the final process of creating an animation. After you have done all the
hard work you can see the output of it. Rendering is a vast topic and even if you have created a great animation the quality of it largely depends on the rendering engine
used to render the animation. It is therefore also a very important stage in the
production of movies. We have given a lot of effects to our movie like lightning,
shadow, etc and all these will be perfectly rendered. Rendering is also a
computationally very intense process. In that sense it is expensive too. There are a
lot of rendering engines that are used in different 3D programs. The real quality of a
3D package depends more or less on the rendering engine it uses. Maya and 3D Max
in my opinion posses the best rendering engines.
Rendering is a very slow process. There are two types of rendering real time and
pre-rendering. Pre-rendering is most commonly used in the production of movies and
is extremely long one. Real time rendering is used in games. To render a 3D image
we need a good 3D rendering graphics engine. The whole rendering process is a long one and can be classified into different sections as following:
Scan line Rendering and Rasterization: Each image consists of primitives. A primitive
is a combination of pixels. Lines and curves are the primitives in 2D images while
rectangles and triangles are the primitives in 3D images. To render a 3D image pixel
by pixels is almost impossible because it may consist of lacs and lacs of pixels. So
3D images are rendered primitive-by primitive. Sometimes we have to render images
avoiding the portions of images without primitives. For such kind of rendering
rasterization is used. Rasterization is supported by most modern graphics processors.
Raycasting
Raycasting is used for the real time rendering of 3D images. It is widely used in
rendering 3D games and cartoon animations. There are different techniques to
identify the color value at different areas of a 3D image in Raycasting. Changing the
color values of areas where 3D points join to the actual color value of the pixel is one
such technique. Raycasting is the best way to render shadows and lightning effects in a 3D image.
I hope you have learned something new. Wish you all the best.
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