Hello! Welcome back to our work on deconstructing architecture.
In our last lesson, you learned how to place features like windows and doors onto the flat, vertical surfaces of a building using perspective division methods. This gave your building facades a sense of order and realism.
Today, we're going to literally "raise the roof." Our goal is to draw roofs and other inclined planes in perspective. This is a crucial step that moves us beyond simple boxes and allows us to create much more recognizable and interesting architectural forms. We'll find that slanted surfaces follow their own unique set of perspective rules.
1. The Core Concept: Vanishing Points Off the Horizon
So far, all our receding parallel lines have converged to a vanishing point (VP) on the horizon line. But what about lines that are sloped, like the edge of a roof or a ramp? They are parallel to each other, so they must converge, but they aren't parallel to the ground, so they won't converge on the horizon line.
Here is the fundamental rule for inclined planes:
The parallel lines of an inclined plane converge to their own Auxiliary Vanishing Point (AVP). This AVP is located on a vertical line that passes directly through the regular vanishing point on the horizon.
- If the plane slopes upwards (away from the viewer), the AVP will be above the horizon.
- If the plane slopes downwards, the AVP will be below the horizon.
The diagram below illustrates this perfectly. Notice how the standard vanishing points (LVP, RVP) are on the horizon, but the Auxiliary Vanishing Point (AVP) for the sloped roof is directly above the RVP.
To see this principle in action, let's watch a short, clear demonstration.
Perspective Drawing 13 - How To Construct Inclined Planes In Perspective
In this first part of his video on inclined planes, artist Dan Beardshaw uses a simple opening box lid to demonstrate how a new vanishing point is created for the tilted surface.
Watch from the beginning to 02:47. Pay close attention to how, as the lid tilts up, its edges converge to a new point below the horizon. When he flips it the other way, the new VP is above the horizon. (Note: He places the VP below the horizon for an upward tilt, which is a valid convention if the hinge is further away. The key principle is that the VP is on a vertical line above/below the main VP).
2. Constructing a Gabled Roof
The most common application of this principle is drawing a standard gabled roof (a roof with two sloping sides meeting at a ridge). Let's build one step-by-step.
We'll use the 'X' method you learned in the last lesson to find the center of the wall where the roof will sit.
Draw a House Using Two-Point Perspective
The article 'Draw a House Using Two-Point Perspective' by Phil Metzger provides a very clear, practical walkthrough for this process. We'll focus on the steps for creating the main roof structure.
Read through the section that includes steps 6 and 7, titled 'Find Perspective Center of Front Wall' and 'Draw Gable'. This shows how to use diagonals to find the center line and then establish the peak of the roof.
Once you've established the front gable, you have everything you need to build the rest of the roof:
- The ridge line (the peak of the roof) is a horizontal line. It will recede towards the same vanishing point as the bottom of the walls.
- The sloped edge of the roof on the far side will be parallel to the sloped edge on the near side. In perspective, this means they will both aim towards the same Auxiliary Vanishing Point.
The following video shows this exact process.
Perspective Drawing 13 - How To Construct Inclined Planes In Perspective
Let's return to Dan Beardshaw's video. He will now apply the AVP concept directly to drawing a pitched roof.
Watch from 02:47 to 04:20. Notice how he first finds the center and draws the front gable, just as we read about. Then, he extends the roof's ridge line back to the main VP and uses the AVP to construct the rest of the roof.
Adding Overhangs (Eaves)
A house without eaves can look a bit like a toy. The overhang of the roof is what gives it a sense of solidity. Constructing this involves extending the planes of the roof and finding their new corners in perspective.
Draw a House Using Two-Point Perspective
Let's go back to the article by Phil Metzger. It has an excellent, detailed guide on how to construct the overhangs.
Carefully study steps 10, 11, and 12. Step 10 shows how to extend the main lines of the roof. Step 11 has a brilliant little inset diagram that solves the puzzle of how to draw the far side of the overhang. Step 12 shows the final connecting line that makes the overhang look solid.
3. An Alternative: The Pyramid Roof
What if the roof slopes up from all four sides, like a pyramid? This is called a hip roof. The construction is a bit different but reinforces the same core skills. Instead of finding the center of a side wall, you find the center of the top surface of your building.
How to Find Roof Angles That Don't Go to Vanishing Points
The video 'How to Find Roof Angles' by Stephen Travers Art demonstrates a very intuitive method for drawing a pyramid-shaped roof. This approach focuses on finding the key points and connecting them.
Watch from 00:39 to 02:57. Observe how he uses the 'X' method on the top plane of the box to find the absolute center, raises a vertical line to define the height, and then simply connects the peak to the four corners.
This method is less about auxiliary vanishing points and more about pure construction, which can often be faster and more intuitive for simpler forms.
Test your understanding!
You've drawn a basic rectangular box in two-point perspective.
- To add a gabled roof, what is the first geometric operation you need to perform, and on which face of the box?
- To add a pyramid roof, what is the first geometric operation, and on which face?
Show answer
- For a gabled roof, you first need to find the center of one of the vertical side walls (the gable end) using the 'X' method. From there, you establish the peak's height.
- For a pyramid roof, you first need to find the center of the top horizontal surface of the box, also using the 'X' method.
Conclusion
Today you've tackled one of the trickiest parts of architectural perspective. Understanding how to handle inclined planes opens up a huge range of possibilities for your drawings, allowing you to create structures that are much more dynamic and realistic than simple boxes.
Key Takeaways:
- Inclined planes have their own vanishing points, called Auxiliary Vanishing Points (AVPs).
- An AVP lies on a vertical line that runs through the corresponding vanishing point on the horizon. The AVP is above the horizon for upward slopes and below for downward slopes.
- To draw a gabled roof, you find the center of the end wall, define the peak, and use the AVP for the sloped edges while the ridge recedes to the main VP.
- To draw a pyramid roof, you find the center of the top surface, define the peak, and connect it to the corners.
- Constructing overhangs is essential for realism and involves extending the roof planes in perspective.
Next Lesson:
We've now blocked out the main forms of a building, including the roof. In our next lesson, we will focus on adding depth and realism by showing wall thickness in openings and adding simple details. This will build directly on what we learned about overhangs today and make your structures feel truly three-dimensional and solid.