Third angle projection is in common use in the USA, Canada, and the UK. The rest of the world more commonly uses first angle. There is no inherent superiority of one projection over the other. When you are making drawings that may be used internationally, it's a very good idea to indicate by a small symbolic diagram which projection is in use. This diagram is usually a side and end view of a truncated cone.
That's what an isometric drawing is: the third dimension is shown at a 30 degree angle to the horizontal. The number 30 isn't magic - any other number in that 'ballpark' would work - but it's an easy number ( a third of a right angle, and it's clearly different from 60 degrees, which is why 45 degrees wouldn't be great), and the resulting drawing makes the 3-D object easy to visualize.
A drawing of a 30 degree angle!
The third angle is (128 degrees) minus (the second angle).
30 Degrees
The third angle is 34.5 degrees
first angle projection and third angle projection.
Neglecting term "opposite".. In third angle projection, what we see are what are we going to draw
First angle is interpretted by the drawing being positioned to the right of the section and third angle is interpretted by the elevation being positioned to the left of the section.
Both third angle and first angle projection display the standard three orthographic views of a part or assembly on a drawing.. The key difference between third angle and first angle is the layout of the part on the sheet.
v Orthographic drawingØOrthographic drawings are orthographic projection drawings. These can be drawn at first angle projection and third angle projections.ØI am going to explain orthographic third angle projection drawing because I use them.ØIf I want to draw orthographic third angles projection drawing I have to follow some rules.ØThese rules are:ØThe view from the front is in the middle.ØThe view from the left is on the left.ØThe view from the right is on the right.ØThe view from the top is on the top.ØThe view from the bottom is on the bottom.ØThe view from the rear/back is on the far right.Example of orthographic third angle projection.Orthographic drawing advantageOrthographic drawing disadvantageEasy to recognized /read and understand by engineers.Hard to recognized by other people then engineers.Doesn't looks like at all to real design/picture.
any country using in second r fourth angle projection r else what r the advantages between first angle and third angle projetion
That's what an isometric drawing is: the third dimension is shown at a 30 degree angle to the horizontal. The number 30 isn't magic - any other number in that 'ballpark' would work - but it's an easy number ( a third of a right angle, and it's clearly different from 60 degrees, which is why 45 degrees wouldn't be great), and the resulting drawing makes the 3-D object easy to visualize.
A drawing of a 30 degree angle!
Yes you can by drawing it on a sphere
isometric drawing create the illusion of 3 dimension by drawing the depth of the object on the both side.. in isometric drawing they are both set on the 30 degree angle..
The third angle is (128 degrees) minus (the second angle).
30 Degrees