Lesson Notes By Weeks and Term v5 - Grade 11

Lesson Video

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Performance objectives

• Define one-point, two-point, and three-point perspective.
• Construct a one-point perspective drawing.
• Construct a two-point perspective drawing.
• Place objects above, below, and on the eye level.
• Convert orthographic projections into perspective drawings.

Lesson summary

Perspective drawing is a fundamental skill in Engineering Graphics and Design. It allows us to represent three-dimensional objects on a two-dimensional surface in a way that mimics how we perceive the world. This is crucial for architects, engineers, interior designers, and even artists. Think about the urban planning proposals you see for new developments in your community, or the designs for new houses in your neighbourhood – perspective drawings are essential for visualizing these projects before they are built. In South Africa, with its growing infrastructure and urban development, the ability to create and interpret perspective drawings is a highly valuable skill.

Lesson notes

Perspective drawing aims to create a realistic representation of a 3D object on a 2D plane. This is achieved by using specific techniques to simulate how objects appear to shrink and converge as they recede into the distance.

Key Terminology: Horizon Line (HL): Represents the eye level of the observer. It is a horizontal line that is crucial for establishing the perspective. Imagine standing on the coast; the horizon line is where the sea appears to meet the sky.

Vanishing Point (VP): The point on the horizon line where parallel lines appear to converge. The number of vanishing points determines the type of perspective.

Station Point (SP): The location of the observer's eye in relation to the object being drawn. While not always explicitly drawn, its position influences the perspective.

Picture Plane (PP): The imaginary transparent plane between the observer and the object. The perspective drawing is essentially a projection of the object onto this plane.

Types of Perspective: One-Point Perspective: Used when one face of the object is parallel to the picture plane. All lines that are perpendicular to the picture plane converge at a single vanishing point on the horizon line. Think of a long road stretching straight ahead – the sides of the road appear to meet at a point in the distance.

Two-Point Perspective: Used when no faces of the object are parallel to the picture plane. Two sets of parallel lines converge at two different vanishing points on the horizon line. This is a more common type of perspective used for representing buildings and other structures.

Three-Point Perspective: Used when the object is viewed from a very high or very low angle. All three sets of parallel lines converge at three different vanishing points (two on the horizon line, one above or below). This creates a more dramatic and distorted view.

Construction Techniques: Let's focus on one and two-point perspective as they are most commonly used in Grade 11 EG

D. One-Point Perspective: Example - Drawing a simple rectangular room Draw the Horizon Line (HL): Draw a horizontal line across your page. This represents your eye level.

Establish the Vanishing Point (VP): Choose a point on the horizon line. This will be your vanishing point.

Draw the Front Face: Draw a rectangle below the horizon line. This represents the front wall of the room, which is parallel to the picture plane.

Draw Convergence Lines: From each corner of the rectangle, draw a line to the vanishing point. These are your convergence lines and they represent lines receding into the distance.

Determine Depth: Decide how deep you want the room to be. Draw a horizontal line between the top and bottom convergence lines. This line represents the back wall of the room.

Complete the Drawing: Darken the visible lines to create a clearer representation of the room. Erase the portions of the convergence lines that extend beyond the back wall.

Adding Details (Optional): You can add details like doors, windows, or furniture by applying the same principles of one-point perspective to those elements. Remember that all horizontal and vertical lines remain horizontal and vertical. Lines going into the page converge at the V

P. Two-Point Perspective: Example - Drawing a simple rectangular building Draw the Horizon Line (HL): Draw a horizontal line across your page. Establish Two Vanishing Points (VP1 and VP2): Choose two points on the horizon line. VP1 and VP2 represent the vanishing points for the two sets of parallel lines that are not vertical. Ensure they are reasonably spaced apart on the page to avoid excessive distortion.

Draw the Nearest Vertical Edge: Draw a vertical line below the horizon line. This represents the nearest edge of the building.

Draw Convergence Lines: From the top and bottom of the vertical line, draw lines to both vanishing points (VP1 and VP2).

Determine Width and Depth: Decide how wide and deep the building will be. Draw vertical lines from the lines converging on VP1 and VP

2. These lines represent the other two vertical edges of the building.

Complete the Top Face: Connect the tops of the vertical lines with lines converging to the opposite vanishing points. These lines will form the top edges of the building.

Complete the Drawing: Darken the visible lines to create a clearer representation of the building. Erase the portions of the convergence lines that extend beyond the building.

Objects Above and Below the Horizon Line: Objects above the horizon line appear to be viewed from below. The top surfaces are more visible. Objects below the horizon line are viewed from above. The top surfaces are less visible, and the bottom surfaces become more visible. Objects on the horizon line are viewed at eye level. You will not be able to see the top or bottom surfaces. Converting Orthographic Projections to Perspective Drawings: This involves using the orthographic views (front, top, side) to determine the dimensions and position of the object.