Why is first angle method preferred over third angle ? Entry posted by umama · January 2, 2015 204,065 views Share Followers 1 What is the difference between first angle method and third angle method in engineering drawing? Why is first angle method preferred over third angle in most of the countries? Alatasi Jamma, Gaurav Jani, Venkat Prasanth and 13 others 15 1 Report Entry
Sarath Chandra_26602 1 Posted January 3, 2015 Report Hi this sarath, according to my knowledge there no much difference between first angle and third angle of projection, just only the difference in projections of the views on the the planes first angle of projection: here object is placed in first quadrant it means object is placed in between the observer and the plane.what ever shape observed from the front u r going to project on the plane which is situated at back side of the object. third angle of projection : here object is placed in first quadrant it means plane is placed in between the observer and the object. what ever shape observed from the front u r going to project on the plane which is situated in front of the object. still if u didn't get clarity go through the below link http://www.technologystudent.com/designpro/ortho1.htm if u got more information about this topic please share with me. CIDesigner 1 Quote Link to comment
gauravd 10 Posted January 3, 2015 Report Difference between first angle and third angle method of projection: 1) In First angle method Object is assumed to be placed in First quadrant whereas in third angle method of projection, Object is assumed to be placed in third quadrant. 2) In First angle method Object lies between the projection screen and observer whereas in third angle method of projection, projection screen lies between the object and observer. 3) As a result, In First angle method, View from left is projected on right side and view from right is projected on left side.In third angle method, View from left is projected on left side and view from right is projected on right side. Detailed Explaination is shown in Image... I think that First angle method is a better practice and as a result it is mostly preferred. ( Projection screen lies rear to the object). The symbol of first and third angle projections itself explains their significance. Symbol of first and third angle method of projection indicates a frustum of cone which is led horizontally on the surface. In case of first angle method of projection, left view of frustum of cone is displayed on right side and in case of first angle method of projection, left view of frustum of cone is displayed on left side. For more details, please visit: vipul panchal, Renias Matsvimbo, Nilesh Mande and 5 others 8 Quote Link to comment
Vinay_49177 1 Posted January 6, 2015 Report Engineering drawing is two-dimensional depiction of various phases of actual objects. To make engineering drawings meaningful and executable, different phases of an object are depicted in two-dimension and placed in a particular way using technique of Projection .... more. pawar Digambar 1 Quote Link to comment
Popular Comment DrD 845 Posted January 7, 2015 Popular Comment Report The original question was, "Why is first angle method preferred over third angle?" I think in the long run, it all comes down to local custom and tradition. Both convery the same information, so neither it truly superior to the other. That said, there is one basis for a good selection that might tilt in favor of one or the other. It is desireable to minimize the number of hidden lines in a drawing, so if one method results in more hidden lines than the other, the second option is preferable. Again though, I think it is a matter of familiarity, what we are all agreed upon, all of which is known as convention. Renias Matsvimbo, hendra w pribawa, saurabhjain and 7 others 10 Quote Link to comment
Shivank Rastogi 18 Posted April 7, 2015 Report Well...in India 3rd angle drawings are the standard...though I also found 1st angle drawings easier to understand... Quote Link to comment
Vic Baylis 0 Posted September 26, 2015 (edited) Report My perspective is.. Third angle offers the view as you would see the object from that side. i prefer third angle. It has a logic to it.The image of a previous video explains itself. with First Angle it's Bottom view at the Top, Left view at the right, and vice versa for both. Wheres the sense of it? Edited September 26, 2015 by Vic Baylis Quote Link to comment
Konda Reddy Gondi 1 Posted September 26, 2015 Report In first angle projection the object is assumed to be placed in first quadrant(The front view is coming above xy-line and top view is below xy-line).In third angle projection the object is assumed to be placed in third quadrant(The top view is coming above xy-line and front view is below xy-line).Any one type of representation can be followed. But internationally, presently first angle projection is preferred, the reason might be in first angle projection the object is directly visible but in third angle projection visualize through transparent planes. Quote Link to comment
DavidS 0 Posted January 10, 2016 Report There really can't be a preferable projection because depending on the first (fornt presumably) view, the number of transparent lines can be the same, especially if you want more than the standard three views. I prefer third angle because that's what I was brought up on... first angle projection is just 'foreign' to me. In the end, it really depends on who your customers and suppliers are. If you're working with American, British, Australian, or New Zealand companies, you will most likely be working in third angle. If you're working with European customers or suppliers, you'll probably be working in first angle. In Asia, it's a complete mixed bag with the standards, because they are typically suppliers to the originator and will conform to whatever standard they're working with on the day. Quote Link to comment
Hanmanth Reddy 0 Posted January 10, 2016 Report In first angle projection the object is imagined to be in first quadrant and object is lies between observer and plane. Plane of projection is non-transparent . Top view comes below front view( elevation ) , right side views drawn to left side of the front view( elevation) when the views are drawn in their relative position In third angle projection the object is placed in third quadrant and plane lie between observer and object .Plane of projection is transparent . when the views are drawn in their relative position top view (plan) comes above front view ( elevation) and right side view drawn to the right side of the front view (elevation ) Both methods can be followed in practice and it depends upon end customer requirement . Quote Link to comment
Sam.watson 0 Posted June 21, 2016 Report What does it mean if the cone is reversed from what is shown above? Does that mean the part is reversed or does it matter? I have a European customer that uses first angle projection, but the cone is reversed from above. First Angle.tif I do not know if the tiff shows, it says I can not see it due to permissions. Quote Link to comment
S.Venkatesh 0 Posted June 27, 2016 Report In fact, First Angle Projection is not preferred at all. It is a 19th century practice which has become Obsolete over 40 years ago. In First Angle Projection, the View of the Object from one side is shown on the opposite side. So View of the Object from Left side is shown on the Right side. View of the Object from the Top - the Plan View - is shown Below the Object. Third Angle Projection is the No.1 Default Choice in Engineering Drawing for over 50 years now. In Third Angle Projection, every View of the Object is placed on the side from which it is viewed. So Plan View is placed Above the Object, Left View is placed on the Left side of the Object, and so on. Quote Link to comment
SU BO DH 0 Posted July 15, 2016 Report Well being an engineer our aim is to made the job in easy and in cheaper cost as consider 1st angle the job is in between plane and observer so it n easy task to work out but in 3rd angle the plane is in between observer and job so 1st angle drawing is an easy task Quote Link to comment
Navaneerhan 1 Posted October 24, 2016 Report On 1/3/2015 at 9:01 PM, Sarath Chandra_26602 said: Hi this sarath, according to my knowledge there no much difference between first angle and third angle of projection, just only the difference in projections of the views on the the planes first angle of projection: here object is placed in first quadrant it means object is placed in between the observer and the plane.what ever shape observed from the front u r going to project on the plane which is situated at back side of the object. third angle of projection : here object is placed in first quadrant it means plane is placed in between the observer and the object. what ever shape observed from the front u r going to project on the plane which is situated in front of the object. still if u didn't get clarity go through the below link http://www.technologystudent.com/designpro/ortho1.htm if u got more information about this topic please share with me. Can you explain the symbol for first and third angle projection? pawar Digambar 1 Quote Link to comment
Raghotham Kashyap 4 Posted August 22, 2018 Report In India, we generally use 1st angle projection. Generally, we view a body as if it is in the first quadrant. So, just for the simplicity of drawing the orthographic views, we prefer first angle projection.As I mentioned before, It is assumed that the HP is rotated clockwise. If you rotate the HP Counter clockwise, then the views will overlap in case of first and third angle projection, and then the second and fourth angle projections will be favourable. So 1st angle Quote Link to comment
Tech Mayur 0 Posted May 1, 2020 Report Difference between first angle and third angle first angle of projection: here object is placed in first quadrant it means object is placed in between the observer and the plane.what ever shape observed from the front u r going to project on the plane which is situated at back side of the object. third angle of projection : here object is placed in first quadrant it means plane is placed in between the observer and the object. what ever shape observed from the front u r going to project on the plane which is situated in front of the object. If you are looking more article like This follow blog.. mechreaders Quote Link to comment
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