问题
In Xcode, I have a .SCN file that was transformed from a .DAE file. I've worked with the person who made the model to set all of the Physically Based (PBR) settings. But no matter what I do, the preview is always black.
Also, if I change the environment to Procedural Sky the model will also display as black.
I'm aware that adding a light to the scene will "fix" this, but should I have to do that? Since it gives my models unrealistic shadows?
回答1:
I changed the Illumination settings to be the _m file in my list of textures. I suppose this has something to do with the way the model interacts with the light in the scene.
回答2:
I just rebuilt my lights, i.e. I had 4 directional lights, so I made a new directional light to replace the first one, manually copied all of the settings including of course the rotation settings, deleted the one I copied from, made a second directional light, copied settings from the second one, etc. I think the problem started for me because I was copying lights from other .scn files, and something between the lights and the PBR materials is getting disconnected.
EDIT: Ok I just realized that rebuilding isn't necessary - the lights were within a group, which is how I copied them over to this scene. I just grabbed all the lights in the group and moved them out of that group and magically they all started working for the PBR materials again. It's a Christmas miracle.
来源：https://stackoverflow.com/questions/48332998/scenekit-material-preview-is-always-black