6.4.1 How to Create a Subrepresentation Based on Multiple Representations

1. Identify the list of supporting representations you will use in your subrepresentation.
2. On the subrepresentation, do the following:

• For each supporting representation, create an “extrametadata” element with a key named “SupportingRepresentation” and set the value of the key to the UUID of the supporting representation. The order in which the representations are specified is important because it determines the index of each supporting representation used in the discrete properties (see below).
• For each subrepresentation patch:

• Add a discrete property value element named "SupportingRepresentationIndex" with the standard discrete property kind named "index". Use this property value element to store the supporting representation index of each selected indexable element of your subrepresentation patch.
• Create an “extrametadata” element with a key named "SubRepresentationPatch[IndexOfSubRepresentationPatch]/ElementIndices/SupportingRepresentationIndex"
• Replace IndexOfSubRepresentationPatch with a specific value and set the value of the key to the UUID of the discrete property.

NOTE: In this case, the standard (non extrametadata) subrepresentation element named “SupportingRepresentation” will be ignored.