Missing polygons when opening file

[Anonymous]

I am using Maya 2018.  I have a model i am working on that is  427 MB.  Maya is flawless when i am working on the model and I save the model on a regular basis but when i open the most recent save, parts of the model are missing.  Is this common in 18 or is there anything i can do to stop this?the gaos ares the floors that are missingthe middle floor is also missing.

[Its_jay]

sometime materials hide part of your model
go to hypershade and assign new material to all model

try this