In this part I will continue what was said in part 1 by showing how shadows are effected by other objects that the main object may be beside or sitting on. This includes things such as cast shadows and reflected light that I mentioned in part 1.
Using the same sphere that was used in part 1 but now placed on a object that could represent something like a table. We will now see how this has changed how the shadows fall on the object.
As before the light is sill coming from the same direction and is sill represented by a yellow arrow.
The first thing to note is that a small band had appeared under the core shadow that has caused the area below the core shadow represented by the blue lines to become lighter. This is the reflected light which has bounced off of the flat plane under the sphere (shown by the yellow arrows in the image below).
This now means that the area that is out of direct light from the light source is now having light reflected onto it from another direction. While this light is not strong enough to light up the area as if it was in direct light it does make the shadows lighter.
Also while not as obvious the core shadow is still there and is now the darkest part of the shadow on the object.
Now that we have an object below the sphere we can see the effects of the sphere blocking the light. This produces what is called a cast shadow. The cast shadow is wherever the light can not make it to the object because it is being blocked by another object. It is possible to draw lines from the light source across the edges of the object blocking the light to find the shape of the cast shadow but this will vary depending on the light source used (e.g. sun, spot light).
In part 3 I will give you some things to keep in mind when attempting to add light and shadow to your drawings.