Explore core techniques for controlling lighting and shadows in real-time 3D environments, focusing on rendering, optimization, and visual effects. This quiz aims to assess and reinforce your understanding of advanced methods for creating realistic and immersive scenes using various lighting and shadow strategies.
Which type of light is best suited for simulating sunlight in a large outdoor environment within a real-time 3D scene?
Explanation: Directional lights are used to mimic sunlight because they emit parallel rays, effectively illuminating large areas uniformly. Point lights emit light in all directions from a single point, making them suitable for bulbs or torches but not for simulating the sun. Ambient light provides general scene brightness but lacks direction and shadows. Spotlights cast focused light in a cone, better for stage or flashlight effects than broad outdoor scenes.
When optimizing a scene with many unmoving objects, which shadow type allows for precomputed shadow information and faster runtime performance?
Explanation: Static shadows are calculated in advance and baked into the scene, offering significant performance benefits for geometry that does not move. Dynamic shadows are calculated in real-time and consume more resources, making them less suitable for static, non-interactive objects. Volumetric and ray traced shadows offer high realism but at a higher computational cost, and are used for more advanced dynamic interactions.
If a baked shadow on a wall appears blurry or blocky in a finished scene, which setting should you adjust to improve shadow detail?
Explanation: Increasing lightmap resolution packs more shadow detail onto surfaces and reduces blurriness or artifacts. Lowering indirect light intensity would only make shadows darker or lighter, not sharper. Decreasing ambient occlusion radius affects contact shadow softness but not baked shadow sharpness. Distance field shadows are for dynamic lighting, not static baked shadows.
What is the most likely cause of shadow flickering, also known as 'shadow acne,' on a mesh that moves under direct lighting?
Explanation: Shadow bias settings control how closely shadows adhere to surfaces; when set improperly, they can cause flickering artifacts known as shadow acne. High polycount impacts mesh complexity but not shadow accuracy directly. Excessive UV padding leads to wasted lightmap space but doesn't cause flickering shadows. Ambient light intensity affects scene brightness, not the accuracy of shadow rendering.
Which strategy is most effective for maintaining high frame rates in a large scene that uses many dynamic lights and moving objects?
Explanation: Using culling and light channels ensures only relevant lights affect certain objects and only visible elements are rendered, greatly improving performance in complex scenes. Increasing shadow map size increases visual quality but may harm performance. Adding more static lights won’t help with moving objects or dynamic lights. Lowering global exposure only darkens the scene without affecting actual performance.