So I have been using 3D extrusion on Photoshop CS6 before, it worked perfectly well. Ever since I upgraded to CC 2015, whenever I extrude a layer (let's say text) it shows a white blank result, only showing the outline of the text when I hover over it. I upgraded to CC 2018 and the same result. Please help.
Are you using the same version of Photoshop as those in this 2018 thread?
If you are using the current version (22.4.x) then, before using 3D, you need to go to Preferences - Technology Previews and check Deactivate Native Canvas. Then immediately click OK and close and restart Photoshop.