Faces that are cut off erase the rest of the mesh

I’ve only had this problem with unity. Using UDK, Cryengine, even havok. Anyway, hypothetically I go on Autodesk Maya, and I cut off faces (basically i cut a hole in an object). So imagine I make a spheere and cut it in half so it makes a bowl shape. When I import it into unity, if you look at it from the side that was cut off it’s completely invisible but when i look at it from the other side it is visible. Is this a modelling error? unity error? am i forgetting to do something?

It is not an error, most shaders only render one side of a face but there are some that will render both. You can edit or create your own that will also do this.

Most of the time you will make a solid 3D model, so you will never see the none rendered side of the face, only the rendered outward facing face sides(as long as your normals are correct).