Symbol 1st & 3rd angle।Draw Orthographic views of a Frustum cone in both 1st & 3rd angle। Formation of Projection symbols of Orthographic projection (First &Third angle).
Drawing par 1st ya 3rd angle ka symbol dikhate hai.Wo kis tarah taiyar hota hai ye hame iss videome samazme aata hai.
We studied the difference between 1st & 3rd angle.We also know both the symbols.But how these symbols are formed and theory behind it is expressed in this video.For that purpose we have to see the pictorial view of the Frustum of right circular cone whose axis is kept parallel to the ground.It's small size circular face has to be to the left side & big diameter to the right side.The Front arrow or observer is looking Front from right side.Initially show the position of F, T & S in Third angle.Draw reference lines.In 3rd angle the Front and side view will form below the reference line.Both the concentric circles to the left side of Front view.A quadrilateral will form in the Front view whose left side is small distance and right side big in length.The axis of the quadrilateral is parallel to the ground means horizontal.The Top view will form above the Front and is same as Front view.In order to get views in the 1st angle simply cross change the position of views from 3rd angle.In case of 3rd angle while looking from Front we know the quadrilateral forms whose left side is small and right side big distance & the two taper lines which are edges.When we are looking from left side, the small circle is seen first & then big circle, both are concentric.Means in Third angle two concentric circles are forming to the left side of the quadrilateral whose left distance is small and right distance big.This is the symbol for 3rd angle.After drawing these views in Third angle simply cross change the position of views to form the views in First angle.In order to get the symbol of 1st angle the quadrilateral will remain unchanged.Only both concentric circles will be to the right side of the quadrilateral whose small distance line is to the left and right side big distance will be observed.This is the symbol for 1st angle.If we consider only Front & Side view of both the figures we will find the difference.In the Third angle, concentric circles comes to the left side of quadrilateral and keeping same the figure of quadrilateral the concentric circles goes to the right of quadrilateral in case of 1st angle.Afterall we followed the difference in symbols of 1st and 3rd angles of projection.
Important Topics Covered :-
1.Carefully observe the isometric view of the Frustum of cone and front arrow.
2.Mark positions of F, T & S for 3rd as well as 1st angle.
3.Draw three views in 3rd angle & cross change the position of F, T & S to get First angle view.
4.If we consider only Front & Side view, the symbol of 3rd and 1st angle will be seen.
5.Complete drawing with lettering and finish.
#difference
#symbols
#firstangleprojection #thirdangleprojection
#orthographicprojection
#technicaldrawing
#machinedrawing
#skilltechdrawing
#sanjaykhair
#frustum
#rightcircularcone
#projectionofsolids
10 сен 2024
