The Basics What is CGI? And what does rendering mean?
Computer Generated Imagery (CGI): The term CGI stands for digital images and animations generated by 3D computer graphics. The term 3D graphics is used synonymously for the CGI image. The process first found practical application in film production/ cinematography, computer simulation, and for creating visual special effects. Characters and entire worlds were brought to life in well-known films such as Star wars, Lord of the Rings or Avatar, through CGI.
In addition to these areas, CGI is used by LIGHTSHAPE, among others, for product visualization and advertising, so in the following we will also concentrate on this focus - our area of expertise. For consumer goods and many industries, the uses of CGI are very diverse. As an image on the website, in print media or for posters at trade fairs, the use of CGI is conceivable in all media, digital or analog.
In addition, other media can be developed. An animation based on the data prepared for the CGI can breathe life into the product. Playing out the data for augmented and virtual reality applications is also possible. Once the data is available, it can be used in many channels.
Rendering (3D rendering): Rendering is the process of calculating images on a computer using special 3D software. To do this, a 3D artist creates a 3D scene based on raw data with camera, lighting and materiality of all objects. The term rendering is also used as a synonym for an image that has been created in the computer.
Strictly speaking, everything you see on a computer screen is rendered. So also the display of web pages, the user interface of the operating system, etc.
Comparison CGI vs. Photography
The limits of photography
A photograph is usually easier to take than creating an image with a computer using 3D data. However, there are some cases where photography reaches its limits or can be as costly as a CG production. Have you ever tried to photograph a machine that is 8m or higher? You will need a very large studio for that.
Alternatively, they show the machine on location. But is there the necessary space for the photographer there? Is that the context and background you envision, or are there things in the picture you don't want to see? These general conditions severely limit classic photography. Afterwards, the photo would need to be post-processed. Depending on how many things need to be retouched, this can be very time consuming and expensive.
What can be difficult to photograph on a large scale is sometimes impossible to photograph on a small scale. You can use the virtual camera to fly into small components, bring out the inner workings, and even show this in motion. Camera settings that would be impossible to achieve with a conventional camera can be perfectly staged and processes, no matter how small, can be communicated in a comprehensible way. Macro shots take on a whole new meaning because there are no limits to imagination and physics.
Of course, what works well in the macro world also makes sense on a larger scale. For example, you don't need elaborate camera slides or cranes to realize settings or film driving situations.
Another elaborate case of photography is photographing prototypes. Prototypes are never quite finished, have the wrong configuration, or require elaborate emotional staging. In the case of a new vehicle, marketing materials need to be developed well in advance of the sales launch. To accomplish this, the prototype must be transported to a special location, set up and photographed. The whole thing then also under secrecy, because one does not want to see the vehicle published prematurely.
With CG technology it is possible to photograph the location and the lighting conditions on site in order to visualize the data set of the virtual 3D vehicle afterwards on the computer with the lighting and reflection photographed on site.
Nevertheless, there are still reasons to photograph products classically. The customer must weigh up how high the cost/benefit factor is for classic photography. A simple photo without much preparation is easy to take. But does this photo live up to the visual claim? Is it worth doing elaborate photo shoots where half of it has to be retouched in the end? In contrast, with CGI everything is possible and you can quickly see what the end result will look like.
But: both ways have their specific advantages and disadvantages. In which cases one or the other approach makes more sense must be decided on a case-by-case basis.
The work of a CG Artist
Once the data from the CAD program has been transferred to the 3D content software, the CGI artist's work begins. CGI artists (also called 3D artists) create CGIs for all conceivable media. One of the first tasks is sorting the data. Since CAD design has different goals than visualization, the data must be restructured. The scene tree reflects the structure and hierarchy of the data set.
Once this is sorted, the objects are assigned materials. Since the objects of the CAD data are usually assigned many different colors in order to be able to distinguish them in the design, the objects must be assigned material properties in the DCC software. These are, for example, color, reflection, transparency, etc. Depending on the complexity of the product, this can take several hours or even days. Once the so-called shading is complete, the scene is set up with camera and lights. Since 3D programs are set up like a real photo studio, cameras need to be set up and lights need to be set. This works similar to a real photo studio.
You place a camera and adjust the lights so that the product is exciting perspective to see and the shape and contours are optimally worked out.
If the background of the image is a backplate, the camera must be adjusted to this backplate. Usually, when photographing the environment, certain camera parameters are already specified, which are passed on to the 3D artist, so that he gets the virtual camera congruent with the real photographed background.
With these steps, the 3D artist's work is almost complete. He only has to convert the 3D scene into a 2D image. Rendering, as described above, can take a few hours. Depending on the image size and complexity of the content. Light distribution, transparency, refraction, shadows, correct reflections are calculated with highly complex mathematical methods to calculate the color of each pixel.
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