.3ds model showing in 2d view, and when selected in 3d view, but not when unselected

I have a .3ds model of a site we need to work on. When I import it, it is clearly visible in the 2d view. In the 3d view, only a few windows and a few components show. If you move the perspective using the mouse, then some other components show but not the whole model.

When you click the area that the model is in, it selects the whole model and you are able to see it highlighted, but as soon as it is deselected it disappears.

i am using Dialux EVO 12.1

Any help would be greatly appreciated

Steve x

P24841-C01-v1.evo

1.95MB

3d model unselected (lots of missing pieces).png

489.13KB

3d model selected & visible.png

1.66MB

2d view of model.png

254.14KB