Oblique Projections

1. Oblique Projections Oblique Projections

2. Projections Classification of projections

3. Oblique Projection Oblique Projection If an observer is considered to be stationed at an infinite distance from an object and looking toward the object so that the projectors are parallel to each other and oblique to the plane of projection, the resulting drawing is an oblique projection. The object is placed with one of its principal faces parallel to the plane of projection. The result is that the front face of the oblique projections is the same as the front view of an orthographic projection. The receding lines are drawn at any convenient angle. The angle that is used depends on the shape of the object or by the position that best describes the shape of the object.

4. Oblique Projection Length of the Receding Lines Oblique drawings made full size (figure a) presents an unnatural appearance due to the distortion of the depth. The appearance of distortion my be reduced by decreasing the length of the receding lines. When the receding lines are drawn true length (figure a) the drawing is called a cavalier projection. When the receding lines are drawn to half size (figure d) the drawing is called a cabinet projection.

5. Oblique Projection Length of the Receding Lines When the receding lines are drawn true length (figure a) the drawing is called a cavalier projection. When the receding lines are drawn to half size (figure d) the drawing is called a cabinet projection.

6. Oblique Projection Choice of Position The face of the object showing the essential contours should be placed parallel to the plane of projection to minimize distortion. The longest dimension of an object should be placed parallel to the plane of projection.

7. Oblique Projection Steps in Making an Oblique Drawing Draw the enclosing box using the overall dimensions of the object with construction lines. Block in the various shapes and details using construction lines. Darken in all final lines.