Photorealistic rendering was adopted quickly by the graphics community and has continued to be popular. This mission statement states that photorealistic rendering is “indistinguishable” from a photo. This mission statement provides photorealistic rendering with a visual “Turing” test and a metric to determine if an image is successful. The mission statement for artistic computer graphics is not one. Researchers are working towards a variety of image creation goals. Artistic computer graphics aims to simulate traditional artistic media, understand the human visual system and communicate effectively with low bandwidth. It abstracts images, enhances learning and improves user interaction.
Computer graphics that emphasize the control of detail is becoming a hallmark of artistic computer art. This control of image detail is often combined with stylization to create the impression of complexity in an image. Artistic images are a natural way to convey information at different levels. Below are seven instances where an artistically generated image can be advantageous.
1. Image reproducibility: Fully shaded, three-dimensional geometry in a technical journal printed only in black and white may not print well. Photographic images, for example, are not as easy to copy and fax as line art images.
2. Medical visualization: Researchers are working to develop artistic algorithms that can be used interactively to visualize volume data in real-time. One example of this is the visualization and manipulation of the electric fields within the human body.
3. Communication of abstract ideas: Our visual system expects characters that are realistically rendered to behave in order to communicate abstract ideas. Nonphotorealistic animation is a method of communicating ideas that go beyond the norms of logic and physicality. It can also be used to communicate ideas in a way that is accessible to a broad audience. This is illustrated by force diagrams in physics textbooks.
4. Evoking the imagination: Line drawings can convey abstract ideas in a way that a photograph cannot. A photorealistic image renders everything in fine detail. This leaves little room for imagination. A nonphotorealistic image, on the other hand, does not show every detail and allows the viewer to participate in the interpretation process.
5. Animation: It is important to keep the viewers’ attention on the key actions and elements of an animation. The big picture can be lost if the viewer focuses on the small details in a photorealistic scene. Nonphotorealistic techniques use an economy of lines, which limits the details in a scene. This makes animators’ job easier.
6. Compression: By not depicting all the detail required for photorealistic images, nonphotorealistically rendered computer graphics images typically take less time to create, can be rendered to the screen faster, and use less storage space. Half-tone images, for example, can be viewed at a distance with the same form from shading cues than traditional computer graphics images. Half-tone images, however, require one tenth to one one-hundredth as much storage space.
7. Communication of Design and Process Completeness: A photorealistic rendering may exaggerate the fidelity of a simulated scene to a photograph. Computer graphics that are artistic can help viewers understand that the scene they see is only a rough representation. Architectural rendering is an excellent example of this phenomenon. Architects have discovered that local building codes and variations can cause last-minute changes to building plans. Clients can be shocked by last-minute changes if they are shown images of the proposed building. This can lead to anger and disappointment. Clients are more likely to accept that the design process is incomplete and that the plans can be changed if they are shown photos of the proposed building. Clients are more likely to accept changes on-site.