Hi,

I am trying to understand a little bit deeper what the Layer Break LOP does (maybe too deeply), by playing with it in FullSceneSetup.hip from the SideFX tutorials, after I discovered the ‘sopmodify1’ in there actually created a new active layer. I wondered what the difference was between this and a Layer Break.

Now the docs says it does two things; 1. create new active Layer and 2. mark previous layers as authored.

Of the starting of an Active Layer I start to understand how it works and how you can use it , and the second thing (mark previous Layers as being authored) I saw reflected when exporting (because it did not create stage/lopnodename.usdnc files). But I wondered how you can check what this means and check if it is done, outside of seeing a Layer Break in the network.

I first thought it was maybe visible in the “Save Control” column of the Scene Graph Layers Panel with varying labels as ‘Explicit’, ‘Implicit’ and ‘Ignore’, but that wasn't what made the difference after checking against what the other nodes did output.

Now is this visible somewhere or is this something hidden that the USD ROP does write out to usd when it notices a Layer Break?
(I have no luxury of examining my usd files, because I am on Non-Commercial)

Thanks, :-)

You left out the most important part of the sentence in describing the second thing that a layer break does:
2. It marks all existing sublayers as having been authored prior to a layer break.
Maybe you understood this and know what it means, and were just leaving out the second half of the sentence for brevity, but I just wanted to point it out for anyone new to layer breaks reading this and wodering what it means for a layer to “be authored”.

But you make a good point that there is no way to see (in the Layers panel or Layer Stack tab of the Scene Graph Details) which layers were authored above a layer break. This information is not stored in the USD of the layer itself, and so inspecting the USD data doesn't let you make this determination. I'll add an RFE to make this information visible in the UI somewhere.