Rendering artifacts may appear when a model has been moved away from the origin or its dimensions are out of this world. It may lead to unconnected/jagged edges and bad tessellation to the surface. The only way to overcome this is to either move the model near to the origin or scale it up/down to the physical size.

In the following images, the model has been moved 2km away from the origin (image 2) and as you may notice, it shows bad surfacing. So always keep in mind to model in real size and keep your scene near to the origin.