Maya Object Disappeared From the Viewport
The model vanished or cannot be seen
Also known as: Maya object not visible · Maya viewport empty · Maya isolate select · Maya frame selection F key · Maya near clip plane · Maya mesh disappeared
Quick answer
When an object disappears in Maya, first select it and press F to frame it. If it is still missing, turn off Isolate Select under the Show menu, check that nothing is hidden in the Outliner, and look at the camera's near and far clip planes in the Attribute Editor, since an object outside that range is not drawn. Also check display layers and the Show menu, which can hide whole object types.
How to fix it
A very small or very large scene scale is a common reason for clipping problems: select the object and look at its scale and position values. Use the Outliner to find hidden objects, and reset the viewport camera if it has been moved or changed. If the object is visible in the Outliner and the framing works, the cause is usually clip planes or a layer.