Renders one-sided polygons with two sides - an inside and outside.
The designer creates and renders polygons with both an inside and an outside. However, most 3D packages and renderers, including OpenGL, can only create and render one sided polygons. Hence the user is required to define whether a polygon is pointing inward or outward. In the case of a dome shape, you would specify that the polygons were pointing inward if the viewpoint were inside the dome and outward if the viewpoint were to be outside the dome.
Turning off the Two Sided Polygons option in the ViewOpenGL menu reveals the faces that are "pointing inwards" in that they render dark (assuming the viewpoint were outside of the model).
The Reverse Face Normals and Orient Faces actions can be used to clean up imported models that may have inconsistent faces pointing inwards and outwards.