this seems related to solid angles because it shows that faces that span greater solid angles relative to some distant point light are brighter.
lucywan
I like how light is currently being abstracted as a rectangle. It makes the process easy to visualize and I'm curious what calculations we'll need later on for different forms of light.
zekailin00
I remember in physics 7b we learned how a surface absorbs more heat when the light from sum is perpendicular to the surface, and a cosine term is also included in calculation. I think lambert consine law is also related the idea taught in physics class. As the angle between surface normal and light increases, less energy is received and irradiance also decreases.
abaqai
The lambert's cosine law is interesting because I believe it can also be applied to other wave entities like heat. For example, it is a well known fact that we have specific climates at different locations of the earth due to its curvature. It’s this curvature that causes different distances between the sun and two unique points on the earth’s surface. I had the impression that because of the change in distance, the heat received at the two points would different (it’s hotter if you’re 5 miles away from the sun as compared to 1000 miles). Now that I think about it, maybe it’s the angle of the heat waves that has more of an effect on the climate as compared to varying distances.
EDIT: I just realized this is mentioned on the next slide... but still curious on how much role the distance has as compared to the angle.
kevintli
I remember this diagram was also used back in Lecture 6 as motivation for the diffuse shading portion of the Blinn-Phong reflection model. It's cool to see it defined more precisely here as irradiance! In Lecture 6 though, there was an extra max to clip the values to be nonnegative — would we not want to do that here as well to make sure the irradiance can never be negative?
ksaralle
it makes sense that irradiance is related to the tilting angle of the surface because for a certain surface, its area is never changed (always A) but the amount of light it receives varies according to how steep the slope is
greeknerd1
This helps build intuition since we see that the greater the amount of surface area that is incident to light, the more energy it receives
this seems related to solid angles because it shows that faces that span greater solid angles relative to some distant point light are brighter.
I like how light is currently being abstracted as a rectangle. It makes the process easy to visualize and I'm curious what calculations we'll need later on for different forms of light.
I remember in physics 7b we learned how a surface absorbs more heat when the light from sum is perpendicular to the surface, and a cosine term is also included in calculation. I think lambert consine law is also related the idea taught in physics class. As the angle between surface normal and light increases, less energy is received and irradiance also decreases.
The lambert's cosine law is interesting because I believe it can also be applied to other wave entities like heat. For example, it is a well known fact that we have specific climates at different locations of the earth due to its curvature. It’s this curvature that causes different distances between the sun and two unique points on the earth’s surface. I had the impression that because of the change in distance, the heat received at the two points would different (it’s hotter if you’re 5 miles away from the sun as compared to 1000 miles). Now that I think about it, maybe it’s the angle of the heat waves that has more of an effect on the climate as compared to varying distances.
EDIT: I just realized this is mentioned on the next slide... but still curious on how much role the distance has as compared to the angle.
I remember this diagram was also used back in Lecture 6 as motivation for the diffuse shading portion of the Blinn-Phong reflection model. It's cool to see it defined more precisely here as irradiance! In Lecture 6 though, there was an extra max to clip the values to be nonnegative — would we not want to do that here as well to make sure the irradiance can never be negative?
it makes sense that irradiance is related to the tilting angle of the surface because for a certain surface, its area is never changed (always A) but the amount of light it receives varies according to how steep the slope is
This helps build intuition since we see that the greater the amount of surface area that is incident to light, the more energy it receives