Técnicas de Proyección Ortográfica en Dibujo Técnico

Orthographic Projection in Technical Drawing

Technical drawing is a crucial aspect of engineering and design, enabling engineers, designers, and other professionals to communicate concepts and ideas in a visual manner. One of the fundamental techniques used in technical drawing is orthographic projection, which involves creating a 2D representation of a 3D object.

Understanding Orthographic Projection

Orthographic projections are created by defining a flat projection plane and then projecting the features of a 3D object onto the plane along lines (or projectors) which are perpendicular to the plane. The image that results is similar to what one would see if they held the object far away and viewed it along the direction of the projectors.

The features of the object that are parallel to the projection plane will appear in their true size and shape, while those on planes not parallel to the projection plane will be distorted along one or both axes. In the most extreme case, a plane on the object which is perpendicular to the projection plane will appear as a line on the orthographic projection.

Display Style

Orthographic projections are not shaded or hatched. They only show edges and boundaries. Visible edges or boundaries (including the extent of curved surfaces) are shown as solid lines, while edges or boundaries which are obscured (not visible from the chosen viewing direction) are shown with dashed lines. The center lines of holes or solid cylindrical features are indicated with a special “long-short-long” line which extends slightly beyond the ends of the feature.

First and Third Angle Projections

Technical drawings can be created using either the first angle or third angle projection. In a first angle projection, the front, side, and plan views are arranged in different positions. The front view is drawn looking straight at the front of the object, the side view is drawn from the side, and the plan view is drawn from directly above. This is the method commonly used in Europe.

In a third angle projection, the front, side, and plan views are arranged in different positions as well. The front view is drawn looking straight at the front of the object, the side view is drawn from the side, and the plan view is drawn from directly above. However, the difference lies in the position of the plan view, which is drawn in a third angle projection to the side of the object, while in a first angle projection, it is drawn directly above.

Application of Orthographic Projection

Orthographic projections are widely used in engineering and design to create 2D representations of 3D objects. They are particularly useful when a design has been developed to a stage where it is almost ready to manufacture, as they provide a clear and accurate representation of the object's shape and dimensions.

In summary, orthographic projection is a critical technique in technical drawing that allows for the representation of 3D objects in 2D form. By understanding the principles of orthographic projection and its various styles, professionals can effectively communicate complex ideas and facilitate the manufacturing process.