How is the Z Focus value determined when using click-to-focus in Augment3d ?
The Z Focus value is determined by the height of the surface that you click on to focus a movinglight.
In the example below, the ground, top of the table and top of the blue box were the surfaces that I clicked on.
Note that if I had clicked on the ground below the table, the Z Focus of the middle fixture would be 0 (because this ground is at 0), but of course the beam would still meet the table surface and not shine through. Also mind your rendering options by clicking onto the "Option" gear on the Augment3d toolbar on the right.