A demonstration of a possible problem with the 3D Box object.
Develop games in your browser. Powerful, performant & highly capable.
I can see all three boxes without changing resolution...
Which version of Construct are you using? I'm using 0.99.82
I just installed a clean, vanilla version of 0.99.82 and I can confirm that yes, this is broke in 82, but it works in 83. So the issue has been fixed for the next build.
put the box futher into the next screen then it will show 3 boxes