Procedural modeling is an umbrella term for a number of techniques in computer graphics to create 3D models and textures from sets of rules that may be easily changed over time.
The output is called procedural content, which can be used in computer games, films, be uploaded to the internet, or the user may edit the content manually.
Procedural models often exhibit database amplification, meaning that large scenes can be generated from a much smaller number of rules.
Often, it suffices to start the algorithm with the same random seed to achieve this.
This is a list of Wikipedia articles about specific procedural modeling software products.