This is an example of using Scene Kit to display 3D models on an iPhone and Apple Watch.
There is a art.scnassets folder which is included in the relevant targets in the Xcode project.
The scene files are referenced in the storyboards.
Note: the file folder needs to be included in the asset path.
The 3D model were converted from blender projects → collada files (DAE) → SceneKit Scenes (SCN).
When converting the models some objects like lights were not converted & removed from the final SCN file. As well, as some other geometries were removed.
The 3D asset usage rights are creative commons.
Thanks to the creators of the 3D models.