There should be a way to disable KDE's desktop effects without System Settings.
On some computers some 3d applications don't work properly
while KDE's desktop effects are enabled.
On these computers the user must disabled KDE's
desktop effects before using any 3d applications.
To disable KDE's desktop effects the user must go to
System Settings> Desktop to disable desktop effects.
The time spent opening System Settings and clicking Desktop
could be avoided if there was a way to disable KDE's
desktop effects without going to System Settings, for
example an icon in KDE's system tray which allows
the user to enable and disable desktop effects.
With Compiz Fusion there is an application called
Compiz Fusion icon.
Compiz Fusion icon is an icon in the system tray which
allows the user to enable and disable Compiz Fusion.
There should be something like Compiz Fusion icon for
KDE's desktop effects.