Can you explain what you mean by "the whole model disappears"?
There are quite some interpretations of what that could mean.
Maybe a screenshot of the state before and after switching on shadows could clarify that a bit.
Out of the blue, there are some rules of thumb when it comes to strange visual effects in 3D graphics:
I hope, at least some of what I wrote was helpful.
Have a nice day!
Thank you Peter for your generous help !
The picture below explains my issue. On the left side we can see the 3D model without shadows and when I activated the shadows everything disapears (Grid, objects ...) my frame looks like the right side of the picture.
For the OpenGL version I'm on 3.0 (Frame Buffer Objects).
That's weird because I never had this problem with the previous versions (12.0,12.2) .
I'll have a look on NVIDIA configuration !
Was there a particular problem (other than the current one with the shadows) that you changed the OpenGL version to 3.0? (I know of cases where that particular version created some problems.)
If that is not the case, could your change it to 3.1 and try shadows again?
By the way: you can display some informations, e.g. about your graphics adapter and driver if you press the button "F" while your active window is a 3D window.
On the bottom there will be a line with some indicators about your visualization:
FPS (frames per second - this will update quite often, e.g. whenever you change the camera in your scene
Nodes: The number of nodes in your scene (If this value is high (e.g., several hundreds of thousands), it indicates a probably bad performance on most computers)
Polygons: The number of polygons in your scene (If this value is high (e.g. several millions), it indicates a possibly bad performance with old graphics adapters)
RAM: A rough estimate of the RAM used for this scene
... and finally the maximally possible OpenGL version your graphics driver claims to support (this value, however, is known to be incorrect in some cases where an obviously incapable graphics adapter claimed to be a magnificent piece of modern technology just before it greatly failed to proof that),
the graphics adapter manufacturer and the currently active driver version.
If there is no line at all, you probably have an AMD card with an older driver or an on-board graphics adapter.
In that case I would definitely recommend updating the graphics driver.
Note that Windows is pretty reluctant in showing your the latest driver so (if you have the possibility) I suggest you go to the NVIDIA site and look for a current and suitable driver there - the difference might be several years of driver development.