Uploaded on
18 Aug 2022
Skill-Lync
Drafting is also spelled as draughting, is popularly known as an engineering drawing. Drafting is the process of representing an object or idea through lines having various thicknesses and makeups.
Low Cost of Drafting Equipment: Manual drafting is created by using drafting equipment like a Pencil, Scale, Mini-Drafter, Compass, etc. The cost of drafting equipment is less compared to CAD Software Packages.
No Cutting End Technology Required: Unlike CAD Systems, you don’t need to maintain the systems with expensive maintenance services. Maintaining the Pencil and Paper is easy to do.
No Need for Subscriptions: In the manual drafting we are not going to use CAD software. If we use CAD software, we need a subscription for the same. It will improve the cost involved in the process.
No training required: Apart from the training which we get while studying, there is no need for the designers to teach the CAD packages being used.
Quality of Design: The CAD software has different tools to create drawings accurately as per the requirement. The quality of the CAD is better compared to Manual drafting.
Easy for Documentation: For manual drafting, we have to maintain a lot of documents. Handling and maintaining the document is a very difficult process in manual drafting. But, in CAD drafting, saving and sharing the documents is very easy. Documents can be saved in the local storage or in the cloud storage.
Modify and Reproduce Faster: Modifying the existing drawing and reproducing the drawing is very easy in CAD drafting. It is very complicated in the Manual drafting process.
Ability to Create a Drawing from 3D Models: In CAD drafting you can directly import any 3D CAD model you can create different views like Front, Side & Top, etc. in CAD drafting.
Following the Standards: Different standards are available in CAD drafting. Based on the standard which you are selecting the views and annotations are automatically added. But, In Manual drafting, you have to know about all the standards. Only then you can create proper drafting.
Time Consumption: The time consumption in CAD drafting is very less compared to manual drafting. Since most of the process is automated by tools CAD drafting will take very less time.
Use of Projections in Drafting:
Definition of Projections:
As an object, it has three dimensions length, width and height. The shapes and size of the object to be represented on a sheet, which has only a two-dimensional plane.
For obtaining the image of an object, various points on the contour of the object are projected on the drawing sheet by means of straight lines and curves. The figure formed by joining various points thus obtained on the plane is the image of the object and is called Projection.
We can define it as “To draw a 3D image on the 2D plane we use various contour points on the objects, plot various plane points, visual rays, straight lines, therefore, image obtained by such plot points on various points on a single 2D plane is known as Projection”.
1) Parallel Projection:
1.1. Orthographic Projection:
1.1.1. Multi-View Projection:
here are two types of Multiview projection. They are given below,
1.1.1.1. First Angle Projection:
In the first angle projection, the plane is beyond the object. The images show the place of the object and plane. The observer initially looks at the object the projection is projected on the plane.
As per the consideration of the drawing sheet, the six different views in the drawings are created as per the image given below,
The common European drafting practice is first angle projection. First-angle projections are not commonly used in the United States.
1.1.1.2. Third Angle Projection:
In the third angle projection, the plane is before the object. The images show the place of the object and plane. The observer initially looks at the plane and the projection is projected on the plane. The plane of the position is assumed transparent in this projection.
As per the consideration of the drawing sheet, the six different views in the drawings are created as per the image given below,
The following are the annotation symbols used in the drafting to annotate the projection method used.
1.1.2. Axonometric Projection:
Axonometric means “to measure along axes”. It is a type of projection used to draw an object when it is rotated in one or more of its axes related to the plane of projection. It has three types. These include,
1.2. Oblique Projection:
Oblique Projection is a method of drawing an object a face parallel to the plane of projection as it is and the other face is drawn at any convenient angle except 90 degree. It has three types of projection. Thus are given below,
1.3. Perspective Projection:
It is a way of projection in which the projection is drawn based on the perception of the observer. The near face of the object looks larger than the far one. This type of projection image looks realistic.
In this article, we have learned about Projection in drafting and different types of projections with suitable examples.
Author
Navin Baskar
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Skill-Lync
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