<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.