cgi

CGI is an acronym with two prevalent meanings in technology and media: Common Gateway Interface, a standard for web servers to execute external programs to generate dynamic web content, and computer-generated imagery, the creation of images and animations with computer graphics.

Common Gateway Interface describes a protocol by which a web server can invoke a program to produce a response to a client request. On each request, the server launches a separate process, passes request data through environment variables and standard input, and reads the program’s output as the HTTP response, beginning with headers. CGI scripts can be written in various languages, including Perl, Python, and C. Developed in the early 1990s, CGI helped enable dynamic pages, but its per-request process model can incur significant overhead. Modern alternatives and extensions such as FastCGI, mod_python, and other application servers are often used to improve performance and scalability.

Computer-generated imagery refers to imagery produced wholly or in part by computer graphics. It covers 3D modeling, texturing, animation, lighting, rendering, and compositing for film, television, advertising, and video games. Rendering techniques range from rasterization to ray tracing, with advances in physically based rendering and global illumination contributing to realism. A typical CGI workflow uses 3D modeling software, asset pipelines, shading networks, render engines, and post-production compositing, often incorporating motion capture and green-screen techniques. Prominent tools include RenderMan, Arnold, V-Ray, Maya, and Blender, and CGI has become essential for visual effects, virtual environments, and immersive media.