Looking at the FilePathTest example in the model bank, the README.txt seems to assert that URIs need to be %-encoded.
However the Collada 1.4 and 1.5 pdf specs say that all URIs (as far as I can see) should be of type xs:anyURI. This page defines the anyURI data type: http://www.w3.org/TR/xmlschema-2/#anyURI. It says:
My interpretation of this is that an anyURI can contain pretty much any character and it is up to the application to %-encode as needed when using the URI to load the associated resource.The mapping from anyURI values to URIs is as defined by the URI reference escaping procedure defined in Section 5.4 Locator Attribute of [XML Linking Language]
Is my interpretation correct?