Lighting & Rendering Flashcards
7 cards from real 3D Modeling practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Lighting & Rendering flashcards as text
What is subsurface scattering (SSS) and for which material type is it most commonly used?
Answer: A technique that simulates light penetrating and scattering beneath a surface; most used for skin, wax, and marble
Subsurface scattering simulates how light enters semi-translucent materials, scatters internally, and exits at a different point, which is essential for realistic skin, wax, and jade renderings.
What does 'depth of field' simulate in a 3D render?
Answer: The optical camera effect where objects outside the focal plane appear blurred
Depth of field mimics the optical behavior of real camera lenses by blurring objects outside the focused distance, adding a cinematic or photographic quality to renders.
In PBR rendering, what distinguishes a metallic material from a non-metallic (dielectric) material in terms of reflectivity?
Answer: Metals have no diffuse component and their reflections are tinted by the albedo color; dielectrics have both diffuse and specular components with white reflections
In PBR, metals have zero diffuse reflection and their specular highlights take on the metal's base color, while dielectrics retain a white-ish specular highlight alongside their diffuse component.
What is a light probe (or irradiance probe) used for in real-time 3D rendering?
Answer: A data structure that captures and stores lighting information at a point in space to simulate global illumination in real time
Light probes capture ambient light information from their position in the scene and are used by nearby dynamic objects to receive approximate global illumination without full ray tracing.
What causes 'fireflies' (bright speckling noise) in path-traced renders, and what is the most common solution?
Answer: They are caused by very bright indirect light bounces with too few samples; solved by increasing sample count or using a firefly clamp/denoiser
Fireflies occur when a ray randomly hits an extremely bright light path with insufficient samples to average it out; increasing samples or using a clamp value reduces their intensity.
What is volumetric lighting in 3D rendering?
Answer: A rendering effect that simulates light scattering through participating media such as fog, smoke, or dust to make light beams visible
Volumetric lighting simulates how light interacts with particles in the air or other media, producing visible god rays, fog, smoke, and atmospheric depth in a scene.
What is the difference between a hard shadow and a soft shadow in 3D rendering?
Answer: Hard shadows have a sharp, defined edge produced by a point light source; soft shadows have gradual penumbra edges produced by area or large light sources
Hard shadows result from an infinitesimally small light source casting a sharp boundary, while soft shadows result from an area light where parts of the source are occluded gradually, creating a penumbra.