Projections
Understanding Projections
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A projection in geometry is a shadow or outline of a shape, resulting from light being cast from a specific direction.
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A plan view is a type of projection, where the view is directly from above. It shows the object as if you’re looking down on it from the sky.
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A front elevation is another view when looking straight on to one side of the object - the front face.
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The side elevation is as if you are viewing the object directly from either the left or the right side.
Calculating Projections
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To determine the shape of a projection, draw a straight line from the light source through each vertex of the object, extending till it hits the surface on which the object’s shadow lands.
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The points where these lines intersect the surface are the superimposed vertices of the projection.
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Connecting these points will give you the outline of the projection, which may differ in shape and size from the original object depending on the light direction.
Concepts to Understand
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Orthographic projection involves viewing an object from the top, front and side views. Unlike 3D drawings, distortions don’t occur in these types of drawings.
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Isometric projection is a method for visually representing three-dimensional objects in two dimensions. It’s used when the perspective of depth needs to be presented in the projection.
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In oblique projections, the viewing direction is not normal (or perpendicular) to the projection plane. This projection results in a distorted and slanted appearance.
Importance of Projections
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Knowledge of projections can be useful in many real-world applications such as design, engineering, and architecture where it’s important to view objects from different angles.
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Understanding projections allows you to visualise how a 3D object will look from different perspectives, thus aiding in problem solving and reasoning questions.
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Extra practice with projections can help enhance spatial reasoning and understanding of shapes as well as their relations in space.