Path Tracing - Week 8

Question 1

Which of the umbra or penumbra is the name for the region around a shadow which is less dark than the center?

Answer 1

The penumbra

Question 2

What type of light allows penumbral effects and soft shadows?

Answer 2

Area light

Question 3

What does SPP stand for? What does it mean?

Answer 3

Samples per pixel, the number of paths being traced through each pixel in the view plane

Question 4

How does the scene’s lighting effect SPP required to get a crisp image?

Answer 4

uniform outdoor lighting converges to decent images much more quickly than darker scenes with multiple dim light sources

Question 5

What magnitude is appropriate for SPP?

Answer 5

Sometimes look at hundred or thousands of samples per pixel to get what looks like a noise free image.

A few tens of samples gives a good idea of a scene but the effect would be very noisy.

Question 6

What can be done over a 2D image generated with path tracing to reduce noise?

Answer 6

Applying a 2D de-noising filter (available in Blender)