Drawing the Inside of a Room in Perspective:
Interior Perspective: When drawing an interior scene, the actual horizon may not be visible. However, we use and "eye-level" line in place of the horizon line. This example uses only one perspective point on the eye level line. Notice that the sides of all objects recede to the vanishing point (VP). You can see through the door that the actual horizon line is consistent with the interior eye-level line. All objects in this example are positioned so that they are parallel with the picture plane. However, if an object were placed at an angle within this scene, all of its lines would not be parallel to the picture plane, would not use the one vanishing point. Those objects would be drawn in two-point perspective.