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ENG Desgin(L6) Isometric & Orthographic Projections - Coggle Diagram
ENG Desgin(L6) Isometric & Orthographic Projections
Isometric Projection
Isometric Axes
In the image on the left, the three axes shown (in blue, red and green) are 120° apart.
In isometric drawing, the vertical lines will also stay vertical.
Difference between Isometric and non isometric drawings:
This is not isometric as the three axes are not 120° at different corners of the chair. The lines seems to be converging towards 3 corners. :red_cross:
This is isometric as the 3 key axis can be found at different corner of the camera. Vertical edges are kept vertical, while the other two axes are 120° to the vertical edges. :check:
3D designs shown using three-dimensional drawings are called axonometric projections, which represent objects without perspective distortion. An Isometric projection is ONE of these axonometric proejctions**
Orthographic Drawings
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.
There's six projections which includes the front, top, bottom, left, right, and back views.
There are six standard projection views—Front, Back, Top, Bottom, Left, and Right—but typically, Front + Top + Right views are used to fully represent a 3D model. Alternate views (e.g., Bottom instead of Top) may be used if they show more detail.
First and Third Angle Projections
In engineering drawings, first and third angle projections are standard methods to represent 3D objects in 2D. They ensure accurate communication of a part’s dimensions and geometry for manufacturing and analysis.
1st Angle Projection:
The object is placed between the observer and the projection plane, so views are projected onto the opposite side, e.g., the top view appears below the front view.
3rd Angle Projection:
The projection plane is between the observer and the object, so views are projected onto the same side, e.g., the top view appears above the front view. Understanding both methods is key to reading and creating accurate engineering drawings.
Types of Lines in Orthographic Drawings
1.Visible lines
Visible lines are solid, thick lines used in engineering drawings to represent features that are visible in a specific view. They clearly define the shape and details of the object for accurate interpretation.
2.Hidden lines
Hidden lines are dashed lines used to show features not visible in a specific view. They reveal internal or obscured parts of an object, helping to fully understand its structure.
3.Center lines
Center lines are drawn with alternating long and short dashes to mark the centers of holes, cylinders, and symmetrical features. They help accurately align and position elements in a drawing.
