Most likely you lack the scale model . If the scale is small, the 3ds Max viewport engine thinks it's thin and insignificant geometry which, as an optimization, you can hide when zooming to a certain distance. It also plays the role of distance geometry of the viewport center. What it farther away (in the system units which can), the quality of its display in the viewport - below. This topic has been discussed a similar question . This happens quite often when exporting geometry with various kinds of CAD programs .
Alternatively, try to select all objects in the scene, and increase again in 10. Should help.
Here Horsham video from Autodesk 3ds Max Learning Channel on this topic:
Highly recommend 😉