Emergency overlays authored on a specializes arc fail to override an unexpected stronger reference on the same properties. Why can that happen?
Select an answer to reveal the explanation.
Short Explanation
In LIVERPS, Specializes sits at the bottom of the strength ladder—below References. So an emergency overlay hanging off specializes can lose to a stronger reference the same way a sticky footnote loses to a stamped city order. Promote the overlay’s strength or change the arc if it must win.
Full Explanation
In LIVERPS, Specializes is the weakest arc—below Payload and References. Emergency overlays authored on a specializes arc can therefore fail to override a stronger reference opinion on the same properties. The overlay may be authored correctly yet lose by strength class. Municipal teams that need overlays to win must promote authoring strength (for example local or stronger layer opinions) or change the composition approach rather than expecting specializes to beat references.
Claiming specializes always outranks references reverses LIVERPS and will misdiagnose the failure as a “payload bug.” Muting is not the only mechanism that can hide overlays; strength losses, non-contribution, and inactive selections also hide content. Saying emergency overlays cannot use composition arcs in OpenUSD is false—overlays routinely use layers and arcs; the issue here is strength, not a ban on composition.
Exam caveat: a specializes opinion can still win against weaker or absent opinions; it fails specifically against stronger classes like References when both speak to the same property. Operational check: for the disputed emergency property, classify each contributing opinion’s arc under LIVERPS. If the overlay is specializes and the blocker is a reference, either override locally above the reference, adjust the referenced content, or restructure the overlay so it is not relying on the weakest arc to defeat a stronger civic reference.