Final answer:
Option D is answer.In 3D graphics, statement (p) that in perspective projection objects appear smaller with distance, and statement (q) equating parallel projection with an infinitely distant viewpoint, are true.
Step-by-step explanation:
The correct answer to the question in 3D graphics, which of the following statements about perspective and parallel projection is true is (D) p and q only. Statement p: In a perspective projection, the farther an object is from the center of projection, the smaller it appears, is indeed a defining characteristic of perspective projection, emphasizing the illusion of depth and distance within a 3-dimensional representation. This effect is often referred to as atmospheric perspective in art, where distant objects are rendered smaller and less detailed, echoing the appearance of things in the natural world.
Statement q: Parallel projection is equivalent to a perspective projection where the viewer is standing infinitely far away, is also true. In parallel projection, lines of sight are parallel to each other, meaning that no matter the distance, objects do not change in size as they recede in space. This contrasts with perspective projection, where lines converge at a vanishing point on the horizon. However, if we imagine the viewing point to be infinitely far away, the lines would appear parallel, thus making the assertion equivalent.
Statement r is false: Perspective projections do preserve straight lines; they do not, however, preserve angles or proportional sizes, which is what creates the impression of depth. Therefore, option (D): p and q only, represents the correct statements about perspective and parallel projection in 3D graphics.