This can fine-tune the way the 3D draft view would work

One very useful setting here is the yon plane value. In certain TAD files; you would notice that you will not see anything being displayed properly in the draft view within TAD . You would see only the sky and the ground.

If you are sure that the Location and the Lookat objects of the view class are correctly positioned; and values for their height and level are also correct; then most likely the overall extents of the model may be so large that TAD cannot process the display

In such a case change the Yon plane setting to something large; say 1000 and try again!