 Hi, I am P. V. Ekhande, Assistant Professor, Department of Mechanical Engineering, Walsh Institute of Technology, Solapur. Today, we will be having discussions related to the projection of planes. At the end of this session, students will be able to draw two shapes of the triangular plane. But before that, just we will have the overlook over the planes. So plane, it is nothing but a two dimensional figure. Plane have two dimensional, one as a length and other as a width with the negligible thickness. So following are few types of the planes. First is a triangular portion in which there are equilateral triangle, isosceles triangle, right angle triangle and scale and triangle. And the other figures are say polygons under which we have the square, pentagonal, hexagonal plane, coctagonal etc. And apart from this, we have the rectangle, rhombus, trapezoid, circle, ellipse. So like this, there are certain types of the regular planes. And apart from that, we can have the irregular planes also. But our study is related to the types which are undercoming the triangular type, square, polygon, rectangle, rhombus etc. So let us study regarding the finding of the two shape of the triangular plane for which suppose the given figure is with the plane ABC. So ABC is the scale and triangular plane which has been shown in the two locations, one as a front view and other as a top view. So front view has been indicated with the name as AF, BF and CF because the points have been taken on the frontal plane and this is according to the first angle projection method. And the bottom figure indicates top view of the plane with the name AH, BH and CH because the points are taken on the horizontal plane that is why the suffix is coming as a edge. So front view and top view, these are the two views which are given. From that, we will find out the two shape of the plane and after getting the two shape of the plane, we can measure the perimeter also. So first step for getting the two shape of the plane is we must get edge view of the plane and for getting the edge view of the plane, we should have the one of the two length line in either front view or in the top view. So we can have the two length line in the front view side or in the top view side. Let us suppose that we want to have the two length line in the top view and for that, we will draw the line parallel from this B point in the front view. So from B point that is a BF, if we draw the line parallel, it will have the intersection on the AC line and the intersecting point is to be indicated as a MF. So now MF BF line that is a MB line is parallel to reference line that is FH line. So this will indicate two length in the adjacent view and that is from B point, we will get the line BHMH in the top view. For that, we will draw the projector from MF point in the downward direction so that it will have the intersection on the respective line. Now which is the respective line over here? The line is AC because when you observe the projector from the M point, it will have the intersection with the AB line as well as AC line. So here the line AC on that the point of intersection is there. So the same will take in the top view. So on AC line, we will get the projection of M point as a MH. Now this line BHMH is in the two length and according to the principle, when we take the plane perpendicular to this two length line that will indicate the point view in the adjacent view and from that point view then we can get the edge view on this side and for that purpose, we have to draw the projectors from the corners of the plane that is AH, CH and from this BH which is already coinciding with the MH. So it is passing over that MH point. So on this projector, we will get the point B1. On the projector of AH, we will get the point A1 and on the projector of CH, we will get the point C1. So in the next slide, you will observe the edge view which is obtained with this procedure. So as told to you earlier, one edge is the reference plane which has been taken perpendicular to BHMH line and because of that, we will get the edge view on this side and for that purpose, we have taken the projector from AH. So the arrow mark which you are observing over here, so on that arrow mark on this projector, you have to transfer the distance of AF from this reference line FH means from FH to AH, AF you have to take the distance and that is to be marked for getting the A point on the projector of AH. Similarly, on the projector of CH, you have to mark the distance of CF from reference line FH, we have to take the distance up to CF and that is to be marked over here and when you connect these two points, you will get the third point on the projector of BHMH which will be at the distance of BF over here. So whatever the distance of BF is here from the FH line, the same will get over here according to the principle. Now this is edge view of the plane and to this edge view, when we take the plane parallel, we will get the tool shape of that on this adjacent side. Means adjacent to this A1C1 line or edge view will draw one line which is parallel and that line is actually the intersection of the auxiliary plane number 1 which is over here and the second plane we are considering, so the line will be called as a 1, 2 that is the reference line 1, 2 which is the intersection of auxiliary plane number 1 and auxiliary plane number 2. So that we will observe in the next slide. So this is the edge view which was drawn earlier and to this edge view, we have taken the plane parallel and that plane parallel is auxiliary plane number 2 which has got the intersection with the auxiliary plane number over here, that's why we are writing this as a 1, 2 plane. Now similar to the previous procedure, we will be drawing the projectors from the corner points of the plane that is A1, B1 and C1. So A1 is one of the corner, B1 is the second corner and third is C1. From C1 we will have the projector and on this projector which point is to be marked, so that is C2 point and for getting the C2 point, we have to transfer the distance from this H1 plane to the respective point. Means whenever we are transferring the distance, one view must be left between the two reference lines. So we are leaving the edge view over here and we are marking the distances of this view on this side for getting the respective points. So on C1 projector, we will have the distance of CH from this reference line, this distance will take in compass and that we will mark over here to get the C2 point. Similarly on projector of A1, we will get the A2 point by transferring the distance of AH and one more thing remember that the distance from the reference line to that point that is to be taken and the same must be marked from the reference line to the on the projector. So you should not mark the point, you should not mark the distance from A1 point, it should be from plane to plane. So from this plane we are marking the distance which has been taken from this view and we will get the A2 point. Similarly on the projector of B, we will get the B2 point by transferring the distance of BH from the reference line H1. So with these three points, then we are going to connect these three points to get the triangle in the true shape. So on this true shape, then you are getting all the lines in the true length and once you get the true shape over there, we can also calculate the perimeter of the plane ABC by measuring the distances from A to B, B to C and C to E, means the lengths of the three sides are to be measured and addition of that will be a perimeter. So this is the procedure of obtaining true shape of the plane when the two views are known to us. So again I am just repeating the procedure, first step is to draw the line parallel over here. This is indicating the true length in the adjacent view, in the top view. That line is the MB line. On the projector of this, when you take the line perpendicular, reference line perpendicular, you will get the point view of that and ultimately we will get the edge view of the plane. So that is the principle for obtaining the edge view. You must take the plane perpendicular to one of the true length line from the plane. So this line is in the true length. That's why we are getting the edge view over here. Again after that, then we will be taking the plane parallel to this to obtain the true shape and for that we are transferring the distances from this for obtaining the A to B to and C to point. So this is true shape of the plane. Thank you.