DITA-OT is designed as a pipeline. Most of the pipeline is common to all output formats; it is known as the
Once the pre-processing is completed, the pipeline diverges based on the requested output format. Some processing is still common to multiple output formats; for example, Eclipse Help and HTML Help both use the same routines to generate XHTML topics, after which the two pipelines branch to create different sets of navigation files.
The following image illustrates how the pipeline works for several common output formats: PDF, Eclipse Help, HTML Help, XHTML, and HTML5.