 Hello everyone, this is Sheila Ratna once a day from Walton Institute of Technology, Solarpur. Today we are going to see the topic sections of solids and in that we will be particularly dealing with the solid cylinder. Learning outcome, at the end of this session students will be able to draw the sectional view of cylinder. I suggest to you all at this point of the video, kindly pause the video and think over the geometry of a cylinder. As we all know, cylinder is a type of solid of revolution. It does not have sides, rectangular sides or triangular sides, neither it has edges. It has a top circular base and a bottom circular base and it has generators which are imaginaries. So there are no defined edges for cylinder. Let us move to the first example. A cylinder base 45 mm diameter and axis height 75 mm is lying on HP with the axis parallel to both HP and VP. It is cut by a vertical section plane inclined at an angle of 45 degrees to VP which bisects its axis. Draw the sectional front view, top view and true shape of the section. So let us proceed with the drawing. Draw XY line which is our reference line. Now as the cylinder is lying on HP with the axis parallel to both HP and VP, depending on this condition we decide the first condition as the cylinder is totally lying on the base on HP. That is it is kept vertically on HP and its axis is parallel to VP and perpendicular to HP. So in this case the top view of the cylinder will be the circle of diameter 45 mm. So let us draw a circle in the top view of 45 mm. So this is the top view of the cylinder. Now let us divide this circle into 8 or 12 parts. It depends upon you whether to divide it in 8 parts or 12 parts. Here we will divide it in 8 parts. We will name the parts as 1, 2, 3, 4, 5, 6, 7 and 8. So this is your top view with the division in 8 parts. To draw the front view let us project all these points in the front view. As the point 2 and 8 being on the same line, point 4 and 6 on the same line we project them in the vertical direction whereas 3 and 7 will form the axis of the cylinder in front view. So in front view it should look like a rectangle of 45 by 75. So this is your front view of the cylinder which is kept on HP with axis perpendicular to HP and parallel to VP and height 75 mm. So naming we can see that we have named it as 1 dash, 2 dash, 8 dash, 3 dash, 7 dash, 4 dash, 6 dash and 5 dash similarly at the top. So this is your complete first stage of the cylinder. Now moving on to the second stage which says that the cylinder is lying on HP with the axis parallel to both HP and VP. When the axis is parallel to both HP and VP it will be seen as a line view in the front view as well as top view. So in this condition, in the first condition we need to tilt this front view in such a way that 5 dash, 5 dash coincides with XY line. I repeat in the first stage front view we need to tilt this in such a way that 5 dash, 5 dash should coincide with XY line. So this is the second front view where axis is parallel to both HP and VP. So these are the namings. So this condition is satisfied that it lies with the axis parallel to both HP and VP. Now further, further completion of the top view project the points from the front view and similarly project the points from the first top view. So you will get a rectangle in the top view as well. Here this is the axis. So in both the views the axis is lying with. These are the namings. So let us move to the cutting plane criteria. It is cut by a vertical section plane inclined at an angle of 45 degrees to VP. So cutting plane makes an angle with VP. As we all know angle with VP is seen in top view. Then the cutting plane bisects the axis of the cylinder. So the cutting plane should make an angle of 45 degrees and it should pass through the center of the axis. So this is your cutting plane which makes an angle of 45 degrees with horizontal. Now consider the points where the cutting plane interacts or intersects with the generators like at 7, 7 it is intersecting at this point. Similarly at 1 and 5 it is intersecting at these points. So we are more concerned or we are more interested in these points. So name the points as point on 33 will be named as 3, P3 point on 24 will be named as P24 point on 15 will be named as 15 point on 5 sorry 6, 8 will be named as P68 and point on 7, 7 will be named as P7. So these are the points which are we concerned about. Now the direction of observation is from this the bottom of top view. So this part the right hand side part of the cylinder right hand side of the cutting section is to be removed and this is the left hand side part is to be retained. So let us project these points P1 to P7 in the front view P3 point will be taken up to 3 dash, 3 dash. Similarly P24 will be taken up to 2 dash, 2 dash and 4 dash, 4 dash. Similarly P1, P5 similarly P6, P8 and P7 by joining these points we are going to get the required section. So these are the points which we are concerned about in the front view. So P1 is the projection of point P15 from the top view up to 1 dash, 1 dash. Similarly P2 is P24 projected vertically upwards up to 2 dash, 2 dash. Similarly we have obtained all the points from P1 to P8. By joining these all points we get the required section view in front view. So this is the sectional front view of the drawing. Now darkening of the edges as the direction of observation is from the bottom of top view so this part has been removed whereas this part has been retained. So darken the outline of the solid in the left hand side part of the cutting plate. Similarly in the front view the left hand side part has to be darkened. This is the complete projection of the cylinder when it is cut by a cutting plane making an angle of 45 degrees to VP. Now let us move to draw the true shape. For drawing true shape you need to draw this cutting plane parallel to XY and plot the points P1 to P8 on this cutting plane. So you can take the distances with the help of compass and directly plot the points over here. Now project these points in the vertical upward direction and similarly project the points from the second front view. The intersection of these points will give you the required section point. So P3 and 3 dash projection from this will give you P3. Similarly P1 from this and 1 dash 1 dash projection from this will give you P1. Similarly P1 to P8 are obtained and by joining this we will get the true shape of the section which is in elliptical form. So this is the required true shape of the section. So here we complete the projection of cylinder which is cut by a cutting plane making an angle of 45 degrees. Thank you.