The assets are all small .jpgs 1 – 2 MB (800×600 px).
I shrunk the .psd down to 1920×1080 and saved as a 2MB .jpg. Same error. I did find that by turning the 3D layer on and using the mouse wheel to zoom in and out (no scrubbing) caused the error to display.
I replaced my final element and now get an error message specifying that 4.5GB exceeds internal limits instead of 9.2.
Apologies if I’m not getting the right information out there, this is new and quite confusing.