Shadows give depth and dimension to illustrations. This effect helps define certain architectural elements and their relationship to each other. Many books have been written on this subject, but I am going to simplify it for you so you don't get lost in the dark.

In this drawing, use of shadow helps define the flat roof overhang and show the depth of the structure underneath it back to the windows

The dark cast shadows define the arches and the depth of the covered walkway.

Here shadows help us to emphasize the trellis structure above the entry door.

Again, use of shadow defines the trellis above the garage doors and shows us that the balconies come out from the building face on the second floor.

In all the above examples, the use of shadow adds depth and contrast (punch) to the drawings.

Add shadows and shapes now have depth and definition. They also visually jump off the page because of the contrast between light and dark areas.

To cast a shadow an object has to be lighted from a source and since we are dealing with buildings outside, our source is the sun. The shadow is the area that the structure blocks from the sun. The area on the structure that is not hit by light is called the shade area. Shade areas don't have as much contrast as shadows. In example #1, the sun light is hitting it from the front left. The plan view shows how this looks from directly above.

In example #2 the sun light is hitting from the front right. From the angle we are viewing the box, the two sides that we see are both lighted and we do not see the shade side (which is around the left corner).

Example #3 shows the box being backlit from above and behind. This is NOT a good way to show off the box because the two sides we see are both in shade. Areas in shade lack detail and if they were in color would appear duller.

In example #4 I added a roof to the box to make it into a house. The roof overhangs the structure below creating an area for the sun to cast a shadow on the front.

The side of the house is going in the same direction as the roof fascia (shown in red in example #4 B) so the shadow will be a consistent width and height across the front. The height of this shadow is determined by the height of the sun in the sky and the amount of roof overhang. For the purposes of this lesson we are not concerned with the time of day, we only want to create a sense of depth and definition. To accomplish this, I showed a shadow with a height that is as wide as the roof overhang. For example, if the overhang of the roof is 2' then I make the shadow 2' in height.

This is a photo of a model depicting what I have drawn in example #4. The arrow shows the direction of the sun light. The shadow from the roof overhang is shallower than the one I've drawn above because the sun is a little lower in the sky in the photograph.

In example #5 the sun is shining on both the front left and right sides, casting a shadow on both sides. The overhang is the same width all around the perimeter of the house but as you notice the shadow has more height to it on the right side. This indicates the sun's light hits the front left side of the house at a lesser angle than the right side. Simply put, more of the left side of the house is facing the sun. This may seem a bit confusing so look at the example below.

If the angle was decreased even more then the shadow on the right side would increase in height (see example below). The angle on the face of the building is created by the roof overhang. And as you notice, the right side begins to become slightly shaded (duller in color than the front left).

If the sun were hitting the two sides equally the shadows would be the same height as in the next two examples.

This photo of the model shows the sun hitting both sides equally.

My preference is to do renderings with the lighting condition as in example #5 because it helps to differentiate each side from the other.

In example #6, I added two wing walls and additional roof. The wing walls cast shadows on the main house and the new roof casts a deep shadow between the wing walls. The downward angle of this shadow is created because the section of roof above is going a different direction than the wing wall. Example #7 shows this a little clearer. The roof fascia (indicated blue) is going in a different direction from the wall (indicated red), casting a shadow angle down and back toward the house, creating a deeper shadow.

In addition, a shadow is now being cast from the far edge of the new roof onto the wall of the main house (see note in example #7). The photo of the model above shows how that looks.

Take a closer look at this rendering from the top of the page. Can you see a similar situation happening? The roof (blue) is going a different direction (in different planes) than the walls and columns (red) causing the shadows to cast an angle down and back to the wall underneath.

This has just been an introduction. Go out and chase some shadows. Study them and see what happens to different architectural elements as they are affected by the sun's light. You can also build a simple model as I did and photograph it in different conditions.

I will be delving into more shadow conditions in a future lesson. Stayed tuned!

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Produced by Jim Stilwell, all artwork copyrighted 2020