You can preload the assets.
prepareObject:shouldAbortBlock:
https://developer.apple.com/documentation/scenekit/scnscenerenderer/1522798-prepareobject
prepareObjects:withCompletionHandler:
https://developer.apple.com/documentation/scenekit/scnscenerenderer/1523375-prepareobjects
Topic:
Developer Tools & Services
SubTopic:
General
Tags: