I have spent quite some time browsing through issues and questions here on the forum and on Gitlab, but so far what I have found doesn’t match my specific case. (Yes, I have really done some effort to figure this out on my own 
)
The general issue is similar to what others have experienced: it prevents 3D viewing of any objects in real-time mode. This means, I can make the simplest PCB; just a rectangle with or without components on it, and when I start the 3D viewer, all I see is the gray gradient background with the XYZ arrows (in shaded 3D) in the lower left corner. No components, no PCB.
This is what I have concluded so far:
I noticed the issue from the moment I began using KiCAD (v5.1)
It prevailed in 5.99 (several revisions), 6.01 and now 6.99 (r1278)
I use 6.99, because it allows me to use my 3Dconnexion space mouse to control the 3D view, and I’m hopelessly lost without it.
There are two things that I believe are significant keys to unlocking this mystery and they are:
- If I switch to ray-tracing mode, everything looks perfect. All components are visible as expected, and the PCB as well with all the details.
- If I lower the opacity of the component’s 3D model below 100, suddenly I can see them. Setting it to 99 is enough for the component to become visible, although translucent.
This effect of only seeing the component with a opacity less than 100, is also apparent in the “3D models” tab of “Footprint properties”. I assume its because that windows uses the same real-time rendering code as the main 3D view window.
I have not been able to verify if the PCB would become visible if it’s opacity was lowered, since I haven’t found any place where I could adjust that property.
I’m doing a lot of 3D MCAD work on my (Windows 11) machine, and for that reason I have an AMD FirePro W8100 graphics card. I realise it is not the most common hardware, and that is why it - or it’s drivers - are one of my primary suspects for this issue. My guess is that KiCAD 3D real-time viewing is accelerated though DirectX or OpenGL APIs, while ray-tracing is done by the CPU. The FirePro range of professional CAD hardware uses their own line of drivers from AMD, so it wouldn’t be surprising if there were some discrepancies between them, and the “normal” gamer-oriented AMD suite.
I feel I have come to roads end with this, and I’m hoping that there is someone else out there who can either confirm or dismiss my suspicions about the AMD drivers, and that eventually a developer may have a closer look at this.
I’m happy to assist in almost any way possible, though I can’t lend out my graphics card; it’s essential to my work on a day-to-day basis.
EDIT:
Fond the solution at the end of this thread: