 Good afternoon, in the academic roaster of IIT Kanpur, this course is named as TA 101, technical arts 101. I am Anupam Saxena, an associate professor with mechanical engineering at IIT Kanpur. You know science has come quite far, about couple weeks ago, physicists were very excited, that they were very close to discovering a particle called Boson. The name comes from two scientists, Bose and Einstein, and this is the particle that is responsible for matter. So, you have many intellectual minds, many intelligent minds working over matter, but how is this fact related to the course? Well, if you are pondering, never mind it does not matter, really never mind it does not matter, not quite, in this course you will have to apply your mind, it does matter. For anything that you would do engineering, you will have to apply your mind, you will have to apply your common sense, because that is what matters in the end. So, this course is called technical arts 101, but I will slightly, I will give you a slightly different name, for me this course is about thinking and analyzing, think T and analyze A, but this is going to be slightly different, in the sense that we are going to be thinking and analyzing only through geometry, no equations, no analysis, no deduction, but only through geometry, through drawings. Anybody have an idea what this picture is about, do you know who this character is, you are right, he is Pu, Vinny the Pu and he was conceived by two people, A. A. Milne and Ernst Scheffer, that is what my 11 year tells me, these are his friends. The point behind the picture, I will try to address this question as to how art got formalized over the years. You know long, long, very long time ago, but not so long ago, people expressed their ideas through sketches and paintings, they probably did not have the grammar, they did not have the vocabulary, they first of all started discussing or representing or expressing their ideas using sketches and paintings. Look at these paintings for instance, these are paintings from a place called Bheem Betika, which is about close to Bhopal about 40, 45 kilometers, 60 kilometers close to Bhopal, Bhopal is about 8 and half hours away from Kanpur, the city. You know this place Bheem Betika has lot of caves, that were accessed by cave dwellers and it seems to have paintings from all these ages, upper Paleolithic, Mesolithic, early historic medieval. You know so this stage here is about 50 to about 100,000 years ago, Mesolithic stage is about 10,000 years ago, Caleolithic is a stage where part of system came in existence primarily with agricultural commodities, early historic. So, if you look at these figures, you would realize that people started sketching or painting schematic decorative in red, white and yellow and medieval stage was what is depicted by geometric linear, Magnes hematite redstone and use of wooden coal. You know so these are paintings from long time ago and if you look at these paintings, you would realize that there is no text, there is no grammar, there is no language, just art and pure art nothing else. You know like this quote here by Riva Kimball long before words were written, thoughts were painted on the walls of the caves. You know so again I would I trade that there was no language, there was no grammar, all we could see were sketches that were painted in the walls of the caves. Some examples look at some paintings, so this is from Sri Lanka from the 5th century, so these are paintings from Ajanta caves again from the 5th century, these are paintings from ancient Egypt 5,000 years ago, some from Shiaway caves France 30,000 years ago and these are from Tokipala caves Peru about 6,000 years from now. You know once again coming back to this quote from Riva Kimball long before words were written thoughts were painted on the walls of the caves. Again look at these paintings no text, no grammar, no language, just art, just colors, of course I mean the text is here, the grammar is here, now inside the paintings keep that mind. So, some more examples these are a couple paintings from Pompeii about 2000 years, Pompeii 5th century even some examples from China, the Tang dynasty 580 to 980 you know, so this was a phenomenon that was in existent throughout the world, well ancient times the period of Razan, Sistine Chapel in Rome on Vatican I guess look at these paintings absolutely fabulous, absolutely fabulous, there are many number over there, look at the use of colors, look at the details you know the features over here. So, people really mastered art when they were added and look at these paintings over here on the roof and on the walls, look at the curvature of the wall, the way they were able to use the curvature and represent paintings amazing, well how about sculptures people again were not behind, again these are examples from the period of Razan, again sculptures from Rome, Peter over here for instance, look at again the details you know the muscles, the bones over here, people became very good at depicting not only their ideas in two dimensions, but also in three dimensions, the question is where they able to do all this without expressing anything on paper in two dimensions, they must be convinced, they must be conceiving you know these ideas somewhere, well let us look at some examples of ancient monuments, you have the Colosseum from Rome, Pyramid from Egypt, Kuduminar from Delhi, Linn Tower of Pizza, Taj Mahal over here, this is something which is very very interesting, so this is a picture of Buddha, in fact not a picture of Buddha, but statue of Buddha, so wooden, largest wooden statue of Buddha in a place called Nara Japan, you know golden temple over here, quite a few monuments from India, Asia and worldwide, once again the question is was it possible for us to have accomplished these monuments, so nicely without using paper and pen or without conceiving these ideas beforehand, what would be your guess, my guess is definitely not, they must have worked quite a bit to be able to concede these ideas, well so this are or rather these are some examples from Gustave Eiffel, he was a French engineer, so these are engineering examples, Garbet Viaduct Railway, it is a bridge over here, look at how efficiently he has been able to use frames to be able to provide enough strength for the rail to cross through this bridge, railway station in Budapest, Maria Pier Bridge again, so if you look at this example and this example very similar in construction, so there is this arch over here that is over the river and then these vertical columns tapering upwards and there is a horizontal bridge, supposed to be really stiff, Iron House in Peru, Athol Tower one of the famous examples of engineering by Gustave Eiffel and his company rather, his team, again statue of liberty, one in France, the other one in the US, close to New York, you know he and his company were responsible to be building about 65 buildings and bridges in Europe and elsewhere throughout the world, once again where they able to concede these ideas and these are by the way engineering ideas, I mean a lot of these structures they happen to be quite stiff, for example these two guys, they happen to be quite stiff, they are able to bear enormous you know vertical load, here the Athol Tower is able to bear enormous wind load, you know I was actually going through a few papers and I realize that or rather people talk about this being conceded by two exponents or exponentials, so this is one exponential curve over here, the second exponential curve over here, fantastic design, but again he and his team members they had to start with a paper and a pen, so they drew a lot of preliminary sketches about the idea and that is true for both the Athol Tower as well as statue of liberty, so these are the internal skeletons, the sketches of internal skeletons of the statue of liberty, so people did work with paper and pen before they conceded all these you know now very well known engineering models, bottom line designers may have been a single person or a team of few or many, I do not know design had to be communicated to those building it, what we now know as manufacturers you know, so designers they would be communicating their design or the ideas to what we call manufacturers these days without that it is impossible, communication could have been possible only through sketches or drawings you know that is the most efficient way in which I know I would be able to communicate my ideas to somebody else. Now the question is you know I would draw sketch or I would draw a few sketches in different way or somebody else would draw these sketches in different way, a third person for example, if he looks at my sketch and if he looks at somebody else's sketch, is it possible for him to strike the uniformity between these two ways of sketching, so the idea is there a way in which we can draw sketches, so that it is easier for the manufacturers to understand these sketches. I will answer that question in a little while later, but first some more examples do you know this guy is none other than a very famous artist and engineer from the Leonardo da Vinci, he was very talented great artist and a great engineer more than that a wonderful visionary you know what was something that I found surprising was his amazing way of describing human anatomy, look at the details of the sketches that he has over here you know I mean of course, he is writing some notes over here he is using some grammar some language, but look at the details the human face typical human face look at the ratio that he is trying to work out skull human skull, a baby in a womb I believe this is a picture that represents or that depicts the golden ratio again pictures of babies fetus or feti once again details over here anatomy the bones and not only did he work with anatomy I mean he also worked with he also used sketches to describe a lot of engineering components that he came up with the ideas that he came up with you know these are pictures from different machines, one of the flying machines that he had conceived around that time 1500 1600 maybe I do not know what this is again a typical mechanical system I believe again a bunch of things over here typical mechanical system lot of pulleys and gears you know so there are many many plenty number gear system I guess primitive glider that he conceived around that time the many of these pictures that represent engineering anatomy medicine you know around the same time and of course he was an artist so not only did he focus on the anatomy and engineering aspects, but he was also interested in art in beauty and one of the final pictures that he that I would show you not not from him so it is a single point perspective of a landscape probably inside of a hall if I am not mistaken it looks like it is all right so to be able to answer that question or to answer that question that I had posed a little earlier was it possible for people to make the way we draw sketches more uniform so he was a person who made it possible his name is Gaspard Munger he was a French he was in French military he was an engineer you know born in 1746 stayed on this earth till 1818 he is a person who is the inventor of descriptive geometry you know picture sketches were used around that time to communicate but did not have any uniformity so that is what he started out with one could draw figures in various ways one could draw paintings sketches in various ways yes we all know that architects builders engineers designers they had tremendous difficulty in understanding these figures I mean fine I mean if I let us say I draw something over here it is you know if I draw something like this perhaps it is not very difficult for you to identify what this is it is a cube for instance or if I draw something here for instance this would be a pyramid with a square base so these are sketches that you know people would understand but how about the dimensions how about relative lengths or angles for that matter so these are things that you know manufacturers architects builders engineers designers they would use to be able to you know accomplish what this sketch would stand for over this sketch would stand for right so these are details which were not present in those sketches manga formalized the technical drawings what we know as orthographic projections the first few lectures will actually be dedicated to these projections and we will learn more about them and other projections or other ways of representing different solids or different drawings later in this course the scheme was quickly adopted by army engineers you know first in France and then worldwide and after the war it was accepted worldwide and formed the backbone for industrial revolution you know look at the buildings we have around us look at the engineering marvels the cars the trains the bullet trains the aircrafts existence of all of which probably would not have been possible unless we had our drawings or sketches being represented uniformly so the objective in this course is to learn technical drawing in theory as well as in practice using drafting tools and free hand sketches once again the objective is to learn technical drawing a technical art in theory and practice using drafting tools and free hand sketches and we will do that you know in the next 40 hours that will devote to this course all right so this is the organizational lectures in laboratory assignments that we have planned week one essentially we will have two lectures on introduction and basic construction week two again two lectures on orthographic projections week three two lectures on orthographic projections week four on isometric projections week five on missing lines and views week six on sections and assembly week seven on oblique projections you know Cavalier and cabinet week eight on perspective projections week nine and ten four lectures over here on lines and planes week eleven will be on auxiliary projections week twelve and week thirteen will be devoted to the topics in section of lines planes and solids and in section and development so in all we will have about 26 lectures and we will have about 13 labs so each lab will be of 3 hour each so lot of work that lies ahead of us all right so lectures will be held in L7 on two days Tuesday and Thursday from 2 to 3 p.m labs will be held in drawing call which is the extension of the non lab and we will probably have one or two labs on AutoCAD which will be held in the new IME building on the third floor all right so your classes divided into 12 groups of I would say 40 students each on average B1 B2 and B3 they will be doing the labs on Tuesday tutors are process Shakti Singh Gupta Prasai N. N. Kishore and Mr. Shantanu the first two from the mechanical engineering the second from or rather third from aeronautical engineering before B5 B6 they will do the labs on Monday and you will have Professor Tareh Professor Bose and Professor or rather Mr. Bhargavaj as your respective tutors sections B7 B8 and B9 are planned for Wednesday with Tarun Gupta Basantalal Sharma and Ashish Dutta from civil mechanical engineering and B10 to B12 they will be doing the labs on Thursday with Rajeev Sinha Javed Malik and Ria Catherine George or from civil engineering the grading policy you know since you are going to be working a lot in your labs we have decided that will assign about 25 percent of your grade to your labs your lab work home assignments you will be doing them quite a bit. So, 10 percent for that missed semester examination 25 percent and semester examination 40 percent. So, 25 plus 25 50 10 plus 40 50 overall 100 percent and there would be certain extra credit assignments that I may be giving they will add to it. So, just in case if you are doing better than what you are or what you should what what rather what you are then of course you will be expecting or you may expect you know more than 100 percent marks and that will be that will be pretty interesting that will be pretty nice. So, the lecture notes are going to be hosted on my webpage home.iitk.ac.n slash tilde Anupam S under courses in the main menu and this is listed under course 2 TA 101 is listed in course 2. We will have a manual for lab and home assignments you know you can seek or you can buy drawing material and books essentially a 3 sheets a 4 sheets sketchbook grade book pretty much like that from noble book store or turn book store in the IIT campus. And we will be using primarily 2 books as a text French Burek and Foster Graphic Science and Design published by Tata McGraw-Hills 2012. And another book by N. D. Putt on elementary engineering drawing Carotter publishing Anand I think this is in Gujarat is it 31st edition 1990. So, 2 books that will be using equipment required you will probably not be able to do your drawings without these equipments. So, this is a mini drafter here a set of set squares this I think is a 45 90 another one 60 30 90 you will have a bunch of erasers what I recommend is a 0.5 lead pencil. So, you will be doing some construction lines and you will be doing some main lines for the construction lines I usually use and recommend 2 H pencil or 2 H lead and for the drawing I recommend H lead a pencil that heads avoid you know spalling of sheet just in case if I have to use the eraser one thing I also recommend is the use of this stencil full of circles you know for smaller circles it is a lot easier and lot neater for all of us to draw circles using this stencil otherwise for larger circles you will have a compass and for weird looking curves you might want to use set of French curves you know to connect the dots and give them a smooth render. So, all these should be available either with noble book store or turn book store in the campus. Now, few things which I would actually want you to note which are very important all labs are to be done in a 3 drawing sheets unless specified otherwise all homeworks again in a 3 drawing sheets unless specified otherwise and all sketches in sketch book it is always a nice idea to come prepared for your subsequent lab and you know working out your sketches in a sketch book would be a nice idea. So, that way you will not be wasting a lot of time you know scratching your head looking left right rather you would know what you need to do in your lab if you adhere to this third point. So, let us get started with some theory we will draw some perpendicular to and from a line what kind of methods to be used for that well. So, let us take a case where a point is not on a line. So, you have line l you have a point somewhere here not on a line and you like to draw a perpendicular from that point on to that line. So, let that point be q you know the easiest thing that you would do is you would place a ruler with one of the edges on the line and then you will take a set square with one of the edges on the ruler. So, this would be I guess a 30 90 or 45 45 set square and you would place the other edge of the set square. So, that it virtually passes to this point and then you would draw this line you know this is how not very difficult straight forward yeah alright. So, another case we have a line here a point here rather it is a similar case, but in this case let us see if we do not use a ruler and a set square what we or how do we draw a perpendicular perhaps just using a compass let us see. So, you know so we will take a compass we will measure this distance and with radius larger than this distance we will draw an arc which would be cutting this line at two points point here ok. So, this is the radius r which is greater than this distance and from this point over here we will draw another arc that is going to be cutting this arc let us say let us say this radius is r 1 which I think is slightly larger than the distance this distance over here and with the same radius r 1 we are going to be making another arc. Now, what we will be having is this point over here and if we join this point with point q this red line will be perpendicular to the line in question. So, this was the case where we had used a ruler and a set square this is an identical case where we did not use these geometrical entities rather we only use a compass these are you know things that you probably remember from the grade school point on a line. So, the previous case was when the point was not on the line what if the point is on the line what you do in this case. So, line l a point on line l q. So, you are going to be drawing an arc with radius r 1 again you will be drawing another arc on the other side of the line again with radius r 1 with radius r 2 or r and center this point you will be you are going to be drawing an arc here and again the same thing. So, with this as center and radius as r. So, this r I think would be slightly larger than r 1 or may be a little more larger than r 1 and the intersection point over here if you join this point with point q you are going to be having a line in red perpendicular to the line in green line l point on the line. Let us say we have another point c which is not on the line we take this distance r distance c q and we draw a large arc with c a center let that arc cut the line at point a our join point a and c and I would probably extend it to insect with the arc over here. Let me call that intersection point as m and m is such that if I draw a line joining m and q this line is going to be perpendicular to the original line l try to prove this again. So, this course is about thinking and analyzing. So, whatever constructions we have discussed so far go back to your hostel rooms and try to work it out algebraically whether really all these red lines in different cases happen to be perpendicular to green lines. I am sure the proof is or the proves rather are not very difficult arc tangents to lines and arcs. So, we have line l we have a point q let us say we draw a perpendicular from q to l you know actually you have studied four cases just about now how to draw a perpendicular to a line let this distance be r that is pretty straight forward you know. So, just take a compass take q a center this as radius drawn out straight forward about this one line l oh that is a big circle all right. So, we have a center for that circle let us call that center c. So, let us let this circle have radius r 1 all right. So, what are we doing here I guess we are looking for an arc which is common to this circle and the line all right. So, let us see how we do that let us take any point on the line and draw an arc you know of radius r. Let us draw a line parallel to this line l you know tangent to this arc let us call this line l prime. Now, with c as center and the radius as r 1 plus r let us draw an arc that cuts this dashed line l prime here. Now, with this as center it is possible for us to draw an arc which is tangent to both the circle and the line and of course, this arc is of radius r. So, I guess the problem was you know given a line and a circle and given a number r how do we draw an arc of radius r that is tangent to both the circle and the line. So, this is how we draw that clearly this distance is r. So, we have a point we have a circle let us say we have an arc we have another arc here. So, the first arc has a center and radius r 1 the second arc has a center and radius r 2. So, this arc with this as center if we draw this arc of radius r 1 plus r and with this as center if we draw another arc of radius r 2 plus r then we will get this center over here and with this center it will be possible for us to draw an arc of radius r which is tangent to both the circle. So, the problem here was you know given a circle with center here radius r 1 another circular arc with center here radius r 2 and a number r how do you draw an arc which is tangent to both these circles. So, this is what the solution is once again all right. So, this is the problem given draw an arc with this as center and radius r 1 plus r draw an arc with this as center and radius r 2 plus r you know get the intersection points of these two arcs right over here with this as center and radius as r draw an arc that is tangent to both these circles. You know how about solving this problem in a slightly different manner again. So, given two arcs with the respective centers and radius r 1 r 2 now draw an arc with this as center and radius r minus r 1. So, r is given to us let us say and draw another arc with this as center and radius r minus r 2. So, with this as intersection point the center and with radius r it is possible for you to draw an arc with this tangent to both these arcs, but you know this would actually be encompassing both these circles. So, you know slightly different angle same problem of course, this radius is r which is larger than r 1 and larger than r 2 all right. So, given line l and l prime you know take any point on this line draw an arc of radius r draw a line which is parallel to this line you know with any point over here on line l prime draw an arc of radius r and draw a line parallel to this line. So, you will actually be having these two dashed lines intersecting at some point and with this point as center and the radius r it is possible for you to draw an arc which is tangent to both these lines you know these are constructs or constructions that you are very well aware of from your grade school line and angle by sectors again. So, this is something that you probably have learnt in the 8th or 9th grade or even earlier. So, given a line so draw this arc where this is center and radius slightly larger than half the length of this line and vice versa you know with this is center the same radius draw this arc over here if you join these two points this essential or this line would essentially be bisecting this line into two parts. So, it is actually going to be a perpendicular bisector it is probably not very clear through this figure, but that is how it is going to be again. So, these two lines with this is center draw an arc. So, this arc is going to be intersecting this line and this line in these two points with the same radius or may be a different radius I guess with this is center draw an arc with this is center draw an arc I guess it has to be the same center go back to your grade school and figure this thing out. So, the intersection point between these two arcs would actually give you a point. So, if you join what am I saying. So, the intersection of these two arcs will give you a point and if you join this point with this point the result essentially will be a line that will be an angular bisector defined by these two lines. So, essentially this angle will be the same as this angle about intersection. So, given a line you know draw another line over here could be of any angle divide this line into three parts three equal parts you know. So, this length this length and this length they are the same join the end point of this segment with the original segment and you know draw these lines parallel to this line and essentially these points will ensure that this line gets trisected divided into three equal parts can we do the same thing for this angle. Let us say it so happens that using a ruler and a compass it is impossible for you to trisect this angle, but there is something called a multiplicator or an angle trisector it is a mechanical device that looks like this. So, if you essentially have this link. So, it is actually a linkage you know. So, if you have this link placed on one of the edges of this angle and this link placed on the other edge it is possible for you to trisect the angle. I am sorry if you place this link on this edge and if you place this link on this edge. So, these two links will essentially be giving you the lines over here and over here in such a way that this angle is going to be divided into three equal parts. So, it is called an angle multiplicator a mechanical linkage that was initially conceived by a b Kempe. So, I will stop now and I would request you to keep thinking and analyzing. So, we will come back in the next lecture.