Query: What is supposed to happen with multiple <materialx> tags in a document ?

[kwokcb]

Query

I just accidently came across this. But if you have multiple <materialx></materialx> blocks what is supposed to occur ?

Currently it will just read the first block and discards subsequent blocks without any error / warning.
A trivial thing, (and assume it's just how the parser works?) but users may become confused if some content does not read in.

[jstone-lucasfilm]

This is a good question, @kwokcb, and my initial thought is that documents with multiple materialx elements should be considered invalid, and should generate a warning in Document::validate. That would allow the current parser behavior to remain unchanged, but would provide guidance for exporters that unintentionally create this category of invalid documents.