<head> and <body>#

Both <head> and <body> are optional. If there is a <head> element, it must be the first sub-element of <asdf>.

The <head> element can contain <source> sub-elements and an optional <reference>. All elements within <head> exist for the whole duration of the scene. If they contain transform attributes like pos or rot, those values are static. Additional <transform> elements can be used in the <body> to offset those values dynamically.

The <body> element can contain <seq> and <par> elements, as well as <clip> and <transform> elements. If the <body> element contains multiple sub-elements, it acts like an implicit <seq> element.