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Isometric & Orthographic Projections - Coggle Diagram
Isometric & Orthographic Projections
ISOMETRIC PROJECTION
When we present a 3D design through the use of three-dimensional drawings, the drawings are also known as axonometric projection.
One of the more commonly used axonometric projections is isometric drawing. Isometric means equal measure. Therefore to produce an isometric drawing, the principal edges are equally inclined to the viewer and they are of the true length. Isometric drawings are constructed on 3 axes that divide the circle equally (
ISOMETRIC AXES
) . They are 120° from each other.
ORTHOGRAPHIC PROJECTION
A simple way of representing engineering design drawings is by using orthographic projections. Orthographic projections are a collection of 2D drawings used to define a 3D model.
FIRST & THIRD ANGLE PROJECTIONS
FIRST ANGLE PROJECTIONS
In first angle projection, the object is placed between the observer and the plane of projection, resulting in the views being projected onto the opposite side of the plane.
First Angle is commonly used in European countries.
The orthographic projections are on the opposite side.
THIRD ANGLE PROJECTIONS
Conversely, in third angle projection, the plane of projection is between the observer and the object, causing the views to be projected onto the same side of the plane. Understanding these methods is crucial for interpreting and creating technical drawings in engineering.
Third Angle Projection is commonly used in U.S.
The orthographic projections are on the same side.
TYPES OF LINE
in
ORTHOGRAPHIC DRAWINGS
VISIBLE LINES
Visible lines
are used to represent features of an object that are visible in a particular view. These lines are typically drawn as
solid, thick lines
to ensure they stand out clearly on the drawing.
They are essential for conveying the shape and details of the object being depicted. In engineering drawings, visible lines help to provide a clear and accurate representation of the object's geometry.
HIDDEN LINES
Hidden lines
are used to represent features that are not visible in a particular view. These lines are usually drawn as
dashed lines
to differentiate them from visible lines.
They help to convey the
internal or hidden
features of an object, which are not directly observable from the outside. Hidden lines are crucial for understanding the complete structure of the object, including its internal components.
CENTER LINES
Center lines
are used to indicate
the centers of holes, cylinders, and other symmetrical features.
These lines are typically drawn as
alternating long and short dashes.
They are important for accurately locating and aligning features on the drawing. Center lines help to ensure that symmetrical features are properly positioned and aligned in relation to each other.