URI (Uniform Resource Identifiers) references are used to refer to external or internal nodes in use elements. URI references are defined in the following form:
<URI-reference> = [ <absoluteURI> | <relativeURI> ] [ "#" <elementID> ]where <elementID> is the ID of the referenced element.
VC supports two types of URI references:
local URI references, where the URI reference does not contain an <absoluteURI> or <relativeURI> and thus only contains an element identifier (i.e., #<elementID>)
non-local URI references, where the URI reference does contain an <absoluteURI> or <relativeURI>. In the current version of VC, non-local references are only supported on the on the same URL as the source document.
The target of the URI reference must be the id of a node inside a VC scene graph description. If the scene graph contains more than one node with the expected id, only the first node encountered in a depth first traversal of the graph is selected as target node.