Civil engineering drawing tutorial pdf

It is often found helpful and convenient to construct and draw the corresponding scale on the drawing than mentioning the proportion in language. On the other hand if a drawing is to be used after decades, the paper may shrink or Md. Taking measurements from such a drawing using the proportion mentioned will give some inaccurate result. But if a scale is constructed an drawn during the preparation of 1st time, the drawn scale will also shrink or expand in the same proportion to the drawing.

Thus if one take measurements with the help of the drawn scale, accurate measurements will be obtained. The ratio of the distance on drawing paper of an object to the corresponding actual distance of the object is known as the representative fraction R. It is to be remembered that for finding RF the distances used for calculation must be in same unit. And being a ratio of same units, R.

Calculation Example 6. Calculate R. Solution: Representative Fraction of the scale for this map,. Find out RF of the scale for this drawing. Solution: Representative Fraction of the scale,. What will be the R. Solution: Here 1 sq. However, sometimes British system is also used. It is important to have clear understanding about unit conversion in both system. Avoid fractions, consider the next integer value. For instance, if maximum length to be measured is 6. For instance if the scale need to measure in feet and inches, number of minor divisions will be If space is limited they can be marked after every 2 division like 0, 2,4,…..

Find R. Solution: 2. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3, 4 and 5. The 1st division is further divided into 10 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 2, 4, 6, 8 and 10 toward left. Thus the scale is constructed and the required distances are indicated.

Draw a plain scale to show units of 10 miles and single miles. Thus we have to construct the scale for 70 miles of maximum distance. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 10, 20, 30, 40, 50 and On a scale one centimeter represents one third of a kilometer.

Construct the scale and show the distance travelled by the car in 3 minutes and 30 seconds. What is the R. Solution: 1 1. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3 and 4. The 1st division is further divided into 6 divisions so that each minor division shows 10 seconds and starting at 0 mark placed earlier the sub-divisions are marked as 10, 20, 30, 40, 50 and 60 toward left.

Thus the scale is constructed and the required time is indicated. Let the given short line AB which is required to be divided into 12 equal parts. Thus dividing is complete indirectly. For instance if the scale need to measure in yards, feet and inches, number of horizontal sub-divisions will be 3.

For instance if the scale need to measure in yards, feet and inches, number of vertical sub-divisions will be At every horizontal sub-division point draw a parallel line to this diagonal line.

At left end a perpendicular of length equal to one major division is drawn and a rectangle is completed considering the mutually perpendicular lines as two sides. The vertical line at left end is divided into 10 equal parts and at each division point a line parallel and equal length of the base line is drawn. Top left corner and the point corresponding to 9hm is connected with a diagonal line. At the remaining 9 horizontal sub-division points parallel lines are drawn to the 1st diagonal line.

Vertical divisions are marked sequentially from bottom toward top at every 2 division as 2, 4, 6, 8 and At all the horizontal major division points vertical lines are drawn. Also show 2 yds. The 1st division is further divided into 3 divisions and starting at 0 mark placed earlier the sub-divisions are marked as 1, 2 and 3 toward left.

The vertical line at left end is divided into 12 equal parts and at each division point a line parallel and equal length of the base line is drawn. Top left corner and the point corresponding to 2ft is connected with a diagonal line. At the remaining two horizontal sub-division points parallel lines are drawn to the 1st diagonal line. Vertical divisions are marked sequentially from bottom toward top at every 2 division as 2, 4, 6, 8, 10 and Construct a scale for this drawing showing meters, decimeters and centimeters and measure 2 meters, 5 decimeters and 8 centimeters on it.

Solution: 20 1. Assume the drawing scale length is 15 cm standard value. Both are acceptable as we have to show a distance only 2m 5dm 8cm on this scale. Let us take 7. Now a horizontal line 15cm long is drawn and is divided into 7 equal parts. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3, 4, 5 and 6. Top left corner and the point corresponding to 9dm is connected with a diagonal line. Maximum measuring length is given here i. Considering a drawing scale length as 15 cm.

So our major unit should be th of meters, 1st sub-unit should be 10th of meter and 2nd sub-unit or diagonal sub-unit should be single meters. Now a horizontal line 15cm long is drawn and is divided into 3 equal parts.

From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, and 2. The 1st division is further divided into 10 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 20, 40, 60, 80 and toward left.

Top left corner and the point corresponding to 90m is connected with a diagonal line. Construct a scale to read miles, furlongs and minimum 20 yards distance and mark 4 miles 6 furlongs and yards on it. Let us assume the drawing scale length is 6 inch. The 1st division is further divided into 8 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 2, 4, 6 and 80 toward left. The vertical line at left end is divided into 11 equal parts and at each division point a line parallel and equal length of the base line is drawn.

Top left corner and the point corresponding to 7 furlongs is connected with a diagonal line. At the remaining 7 horizontal sub-division points parallel lines are drawn to the 1st diagonal line. Vertical divisions are marked sequentially from bottom toward top at every 2 division as 20, 60, , , and The scale should be such that 4mm length is represented by 10cm and it should be able to measure upto 5mm.

Construct the scale and measure 3. The 1st division is further divided into 10 divisions and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 0. Top left corner and the point corresponding to 0. Vertical divisions are marked sequentially from bottom toward top at every 2 division as 0. Draw a scale to represent 6 km by 1 cm and to show distance upto 60 km. From left staring 0 at 2nd division major units are marked sequentially toward right as 0, 1, 2, 3…… and 9.

The 1st division is further divided into 6 divisions so that each sub-division represents 10 seconds and starting at 0 mark placed earlier the sub-divisions are marked after every 2 division as 20, 40 and 60 toward left.

Top left corner and the point corresponding to 50 seconds is connected with a diagonal line. At the remaining 5 horizontal sub-division points parallel lines are drawn to the 1st diagonal line. Construct a plain scale to show meters and decimeters, when 3 centimeters are equal to 2 meters and long enough to measure upto 5 meters.

Show a distance of 2 meters 7 decimeter and 4. Construct a plain scale that can measure 1m to 50m. Show a distance 38m on the scale. Construct a scale to show miles and furlongs, when 2. In a certain map 1 acre represents square kilometers of land area. Construct a scale for a portion of that map which can measure in kilometers and its 1st decimal point.

The scale should be long enough to measure upto 9. Construct a plain scale to measure a maximum distance of 55 km and show the measurement of 42 km on it. The volume of a room is cubic metre.

It is represented by a volume of 80 cubic cm. By measuring R. Also show the measurement of 12 metre on it. The distance between Dinajpur and Joypurhat railway station is km and it is covered by the Drutajan Express in 4 hours.

Draw a plain scale to measure the time upto single minute. Take R. Calculate and show the distance covered by the train in 45 minutes on the scale. Construct a diagonal scale to read meters, decimeters and centimeters and long enough to measure upto 5 meters when 1 meter is represented by 3 centimeters.

Indicate on the scale a distance of a. Construct a diagonal scale of R. A plan of a house 12 cm represents m. Construct a diagonal scale to read metres to one metre and show the measurement metres on it.

The distance between two station is km. On a map it is represented by a 12 cm length line. Construct a diagonal scale to show kilometers and to measure a distance of km. Find the R. Also mark a distance 46 metres and 5 decimetres on it.

Ina drawing of machine parts, the original shapes are magnified 50 times. Construct a scale to measure upto 2nd decimal point of a single millimeter and long enough to measure upto 4mm. Show a length of 2. A person is running at a speed of 6 kmph. Why have you studied scale? Define scale. When scale becomes necessary? Why have you learned to draw scale? In which situation scale is to be drawn along with the drawing? Classify scales according to scale size. Define each type and give practical examples.

Classify scale according to measurement capacity. Define each type. Which scales are usually used by engineers? Differentiate between plain and diagonal scale. Which information you think necessary to construct a scale? Define R. What is the unit of R. Give logic to your answer. What do you understand when an R. It is mentioned in a drawing that R. What is its meaning? On a map of Bangladesh you measured the distance from Dinajpur to Dhaka as 6 inch.

Actually the distance is miles. What should be the possible R. A 15 cm scale measures a maximum length of 10 km. What is its R. If 9 hectares of area is represented by 1mm2 in a map, what is the value of R. During the construction of scale why the zero notation placed at 2nd division? How can you divide a 1mm line in 7 equal parts? To provide necessary information about an object to the manufacturer or to any other concerned party, it is usual practice to provide projection s of that object.

If straight lines rays are drawn from various points on the contour of the object to meet a transparent plane, thus the object is said to be projected on that plane. The figure or view formed by joining, in correct sequence, the points at which these lines meet the plane is called the projection of the object. Pictorial Projection 3. Perspective Projection 7. When the projectors are perpendicular to the plane on which the projection is obtained, it is known as orthographic projection.

Following six views are possible in orthographic projection of a solid object. Top View b. Front view c. Left View d. Right View e. Rear view f. Bottom view Fig. They have the advantage of conveying an immediate impression of the general shape and details of the object, but not its true dimensions or sizes.

Pictorial projections may be of two types as a. Axonometric b. Oblique 7. Axonometric projections are classified according to how the principle axes are oriented relative to the projected surface. There may be three types as: i. Isometric ii. Dimetric iii. Trimetric Fig. The angle is usually kept This may be of two types: i. Cavalier Projection: In this case, the dimensions along all the axes are plotted in full scale. Cabinet Projection: In this case, the dimensions along the diagonal axis are plotted by reducing it to half of the actual value.

Dimensions along other axes are plotted in full scale. In case of perspective projection observer is considered to be at finite distance where in case of any other type of projection observer is considered to be at infinity. In short, orthographic projection is the method of representing the exact shape of an object by dropping perpendiculars from two or more sides of the object to planes, generally at right angles to each other; collectively, the views on these planes describe the object completely.

Descriptive geometry is basically the use of orthographic projection in order to solve for advanced technical data involving the spatial relationship of points, lines, planes, and solid shapes.

The most common means of understanding these types of orthographic projection is - The Glass Box method. It can be suitably used for understanding the generation of orthographic views. The box is unfolded to obtain the arrangement of views. In figure 7. The line of sight is always perpendicular to the plane of projection, represented by the surfaces of the glass box top, front, and right side. Projection lines C connect the same point on the plane of projection from view to view, always at right angle.

A point is projected up on the plane of projection where its projector cuts that image plane. In the figure 7.

When it intersects the horizontal plane top plane of projection , it is identified as 1H, when it intersects the frontal plane front plane of projection , it is identified as 1F, and where it intersects the profile plane right side plane of projection , it is labeled 1P.

On these planes, views of the object can be obtained as is seen from the top, front, right side, left side, bottom and rear. Consider the object and its projection in fig. In actual work, there is rarely an occasion when all six principal views are needed on one drawing. All these views are principal views.

Each of the six views shows two of the three dimensions of height, width and depth. In general, when the glass box is opened, its six sides are revolved outward so that they lie in the plane of the paper. And each image plane is perpendicular to its adjacent image plane and parallel to the image plane across from it. Before it is revolved around its hinged fold line reference line.

A fold line is the line of intersection between any hinged adjacent image planes. The left side, front, right side, and back are all elevation views. Each is vertical. The top and bottom planes are in the horizontal plane. But in most cases the top, front, and right sides are required. Sometimes the left- side view helps to describe an object more clearly than the light side view.

Orthographic views are arranged in two techniques as a. First Quadrant Fig. When an inclined or oblique line is to be projected it is helpful to identify and draw the end points and then joining them to obtain the projection. Parallel Inclined Fig. Oblique Fig. The edges, intersections, and surface limits of these hidden parts are indicated by a discontinuous line called a dashed line or hidden line.

Particular attention should be paid to the execution of these dashed lines. If carelessly drawn, they ruin the appearance of a drawing. All the center lines are the axes of symmetry. Hidden portions of the object may project to coincide with visible portions. Center lines may occur where there is a visible or hidden out line of some part of the object.

Since the physical features of the object must be represented full and dashed lines take precedence over all other lines since visible out line is more prominent by space position, full lines take precedence over dashed lines. A full line could cover a dashed line, but a dashed line could not cover a full line.

When any two lines coincide, the one that is more important to the readability of the drawing takes precedent over the other. The following line gives the order of precedence of lines. Full line 2. Dashed line 3. Careful line or cutting — plane line 4. Break lines 5. Dimension and extension lines. Crosshatch lines. The points which are connected by lines in original object should be connected in the vertical plane. All other 5 views can be obtained in similar way. The plane of projection vertical, in case of front view should be parallel to the face for which views are being drawn.

For example, in case of top view the plane will be horizontal. In the projection there is a relationship of different views. It is usual practice to draw the front view first, then top and side views are drawn with the help of the vertical and horizontal projection lines.

This can be done using T-square, set-squares and compasses. Here only the figure C requires the use of compass in addition to T-squares and set- squares. The spacing between views has to be determined or decided beforehand and if equal spacing is needed then fig. A can be followed and if a different spacing is needed then fig. B can be followed.

Sufficient space should be provided in order to give dimensions avoiding any crowding and also excessive space should be avoided. If not mentioned or required otherwise 30mmmm spacing can be provided between two successive views. Position of this line depends on the spacing requirement between side view and front view. If equal spacing is required then the line should originate at the corner of the front view. These lines will cut the diagonal line. It is to be noted that for 1st angle projection the lines should be projected according to position of views.

For example to draw top view, vertically downward lines need to be projected from front view so that the top view is generated below the front views; for getting right side view horizontal lines from front view are to be projected toward left and so on.

The length along the third axis cannot be shown in same view. This makes it difficult to understand them and only technically trained persons can understand the meaning of these orthographic views. A layman cannot imagine the shape of the object from orthographic projections.

To make the shape of an object easy to understand for both technical persons and non-technical laymen pictorial projections are used.

Most commonly used pictorial drawing is Isometric drawing. When a drawing is prepared with an isometric scale or otherwise if the object is actually projected on a plane of projection, it is an isometric projection. For this purpose the object is so placed that its principle axes are equally inclined to the plane of projection.

In other words, the front view of a cube, resting on one of its corners is the isometric projection of the cube as shown in fig. But as the object is tilted all the lengths projected on the plane appears to be shortened and thus they are drawn shortened in isometric projection.

In the isometric projection of a cube shown in Fig. The extent of reduction of an isometric line can be easily found by construction of a diagram called isometric scale. For this, reproduce the triangle DPA as shown in Fig. Mark the divisions of true length on DP. Through these divisions draw vertical lines to get the corresponding points on DA. The divisions of the line DA give dimensions to isometric scale. The lines that are parallel on the object are parallel in the isometric projection.

Vertical lines on the object appear vertical in the isometric projection. A line which is not parallel to any isometric axis is called non-isometric line and the extent of fore- shortening of non-isometric lines is different if their inclinations with the vertical planes are different.

Drawing of objects is seldom drawn in true isometric projections, as the use of an isometric scale is inconvenient. Instead, a convenient method in which the foreshortening of lengths is ignored and actual or true lengths are used to obtain the projections, is applied which is called isometric drawing or isometric view. This is advantageous because the measurement may be made directly from a drawing. The isometric drawing is An isometric drawing is so much easier to execute and, for all practical purposes, is just as satisfactory as the isometric projection.

Box method. Off-set method. In this method, the object is imagined to be enclosed in a rectangular box and both isometric and non-isometric lines are located by their respective points of contact with the surfaces and edges of the box. It is always helpful to draw or imagine the orthographic views first and then proceed for isometric drawing.

In the off-set method, the curved feature may be obtained by plotting the points on the curve, located by the measurements along isometric lines. If there are some inclined lines in the plane it will be helpful to enclose the plane with a rectangle and then obtain the projection with reference to the sides of that rectangle. ABCD is the required isometric projection. This can also be drawn as shown in Fig.

Arrows show the direction of viewing. Arrow at the top shows the direction of viewing. Similarly the fig. The line 3-A will intersect the line at point M. Similarly obtain the intersecting point N. With center 3 and radius 3-D draw an arc AD.

Similarly the isometric views can be obtained on vertical planes as shown in fig. Then the isometric box is constructed and the orthographic views are reproduced on the respective faces of the box. Finally by joining the points relating to the object and erasing unnecessary lines the isometric view is obtained. In a specific isometric drawing three maximum faces can be shown. Usually front view, top view and either left or right side view are selected.

Use set square to make angles. Remember to cut height along vertical isometric axis. To do this, draw 2 parallel lines of each isometric axis at the end points of other two axes. Erase the non- existing lines.

Compare the orthographic views with your obtained Isometric views. If not, you are done. Step-1 b Step-2 Step-3 c d Step-4 e Fig. Draw isometric view from the orthographic views given in figures below: Md.

Draw isometric view of a hexagonal prism 30mm sides and 60mm height. Solution: Draw the orthographic views first. Following section 7. For projecting the hexagonal top view on the top face of isometric box follow section 7. Draw isometric view of a cone with base diameter 30mm and axis 50 mm long. For projecting the circular top view on the top face of isometric box follow section 7. Exercise and Assignments: 1. Draw orthographic views of the following objects wooden objects available : 1 2 3 4 Md.

Draw orthographic views for the following pictorial views Assume arbitrary dimension : 1 2 3 4 Md. Draw necessary orthographic views to represent i. A reading table ii. Sitting chair iii. Twin seats of university bus. Laptop computer v. Wall clock. D-box of HSTU. A pentagonal pyramid. A Cylindrical pen holder.

An oval shaped paper-weight. Draw isometric view of a rectangular plane having length of sides as 10 cm and 15 cm when its plane is a horizontal and b vertical. Draw isometric view of a square prism with a side of base 5cm and axis 15 cm long when the axis is a vertical and b horizontal.

Draw isometric view of a cylinder with base diameter 10cm and axis 15 cm long. A pentagonal pyramid of side of base 30mm and height 70mm is resting with its base on horizontal plane. Draw the isometric drawing of the pyramid. Draw isometric views of i. Prepare isometric drawing from the given orthographic views.

Use assumed value for missing dimensions 2 1 3 4 5 6 Md. Why have you studied projection? Define projection. Why it is necessary? What do you mean by projection plane, projector and view? Show in a sketch. Classify projection and define the types. What are the possible orthographic views of an object?

Are all the orthographic views necessary to describe an object? If not, how will you choose the necessary views? Describe the glass box method.

What do you mean by 1st angle and 3rd angle projection? Which one is British and which one is American System? Which one is easier and why? Differentiate between 1st angle and 3rd angle projection. Show the arrangement of views in 1st and 3rd angle projection system. Which lines are projected to their actual length? Which lines are not projected to their actual length? How will you obtain projection of such lines? How do you represent a hidden edge in a particular view? How do you represent a hole in orthographic view?

What is the order of precedence of line in orthographic projection? What will you do, if a solid line and a hidden line occur at the same location? What will you do, if a center line and a hidden line occur at the same location? How do you obtain views by diagonal line method?

What is the standard spacing to be maintained between views? How to control space between views in diagonal line method? What are the advantages of orthographic projection?

What do you mean by pictorial projection? Classify it. What is the difference between axonometric and oblique projection? What are the different types of axonometric projection? Why they are so named? What is the difference between isometric, diametric and trimetric projection? What is the difference between cabinet and cavalier projection? What do you mean by perspective projection?

How does it differ with pictorial projection? Why the object appears to be shortened in perspective projection? Why isometric projection is the most commonly used pictorial projection in engineering drawing?

What are the advantages of isometric projection over other types of pictorial projection? In which position of object its front view becomes its isometric view? How the object is rotated to obtain its isometric view? Why are the objects appeared to be shortened in case of isometric projection?

What is the percentage of shortening? What is isometric scale? How it is constructed? Which one is advantageous and why? What do you mean by isometric and non-isometric lines? How isometric drawing are constructed by box method. Why is it helpful to draw orthographic views before drawing the isometric view of the object? In the box method, how will you decide the isometric axis for plotting width, length and height?

Ghose, Civil Engineering Drawing and Design, , 1st ed. Amalesh Chandra Mandal, Dr. Quamrul Islam, Mechanical Engineering Drawing, , 1st ed. David L. Goetsch, John A. Nelson, William S. Dhawan, A Textbook of Machine Drawing, , 2nd ed. Shah, B. Rana, Engineering Drawing, , 2nd ed. Venkata Reddy, Textbook of Engineering Drawing, , 2nd ed. Gurcharan Sing, Subhash C.

Sharma, Civil Engineering Drawing, , 7th ed. Wikipedia Documents, power point presentations and lecture notes freely available over internet. Lesson Plans 2. Operation Sheets By tsegey mekonnen. The value of a will unveil itself after drawing the part you are given information about. Autocad is primarily for generating 2d sketches. Hi friends here i bought you the most useful material for your autocad designs. This exercise was first introduced in this autocad quiz.

Few more autocad exercises exercise 1. This course is designed to provide civil engineering undergraduates with basic understanding of the theory and practice of engineering drawings. Apr 11 explore stretchflans board autocad 2d on pinterest. This book contains 2d exercises and 50 3d exercises. It does have some ability to visualize those 2d sketches in 3d and even to make 3d objects but its primarily built around a flat sketch based workflow.

Feel free to check it to find out what the height of the image is. This book does not provide step by step instructions to create drawings in autocad. Autocad 3d exercises pdf for mechanical engineering free download.

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