Projections of Straight Lines – Mid point problem

straight-line-midpoint-solutionClick this link (power point slide show)to see the illustration of Mid point problem

Given the position of mid point in VP and HP, true length, theta and phi.


25 responses to “Projections of Straight Lines – Mid point problem

  1. girish gopal agrawal

    This site is excellent for the knowledge of midpoint problems

  2. Dear Students, I hope you’ll do the reverse if the projections are given and true length and true inclinations are asked. Also check out for the position of given end points.(if one end is near HP, then its front view is neared to reference line, if other end is neared to VP, the its top view is nearer to reference line)

  3. this site is good for mid point problems but a little bit slower explanations would make us understand clearly ……………..

  4. what book can i follow sir (author)

  5. Respected Sir,
    Q 1. Line PQ has end P 10 mm above HP and 50 mm in front of of VP .Elevation of the line is inclined at 30 deg to HP and the plan is inclined is inclined at 60 deg to VP .End Q is in the second Quadrant and at equal distances from the HP and VP. Draw proj of this line and find i)true length and true incl . ii)dist of Q from HP and VP iii)H.T and V.T.

    Q2. There are two poles of 2m and 3m height on two different sides of the wall .A straight wire is tied on the top of these two poles.One pole is 1.5 m behind the wall and the other is 2m in front of the wall .The distance, measured along the ground and parrallel to the wall between two poles is 3m.Find the length of the wire .Thkness neglected of pole and wire. Assume suitable thickness of wall . At what height the wall will touch the wire? What is the distance of the midpoint of the wire from the wall and the ground?
    please reply at the earliest..
    Thanking you..

    • ANS to Q1.
      Mark p &p’ as per question.In question ,its clear that point Q in second Quadrant,and also it is equally placed from the HP&VP.As we know,when the point is placed in second quadrant,its plan and elevation should in one plane,In this question it will be above the reference line.And from the question,we can conclude that q&q’ should be the same point.(because, consider the point Q independently,its plan and elevation will be the same point) .So the intersection of the lines, which makes 30 deg. to HP(from p) and 60 deg. to VP(from p’) will be the point Q(its plan &elevation-q,q’).Rest of the problem we can find out manually.
      And pardon me,i don’t know the answer of the second…(I am first year Mechanical student@LBSCE,Kasargod,Kerala)

  6. the top view of a 75mm long line measures 55mm the line is in v.p. its one end being 25mm above the h.p. draw its projection.

    • Dear Mishra,
      Your question is not clear.
      If the line is in VP then the front view will be only a point not the foreshortened length of 55mm as you’ve asked.
      Perhaps it should be one end is in VP and other end is 25mm above HP.
      then in this case use a secondary plane (side view) and project from the side view the front view and top view.

  7. Sir can give some important ppt files to my mails related to our LINES and PLANES

  8. Hi everyone I’m very by all these amazing topics really thank u so much,but I’m a student in Bucharest university but actually i didn’t understand anything in this subject cause our teacher didn’t explain to us anything or we can say specially me,cause I’m from Arab world so , i want to know how can i be better in this subject cause i want to give this point A(50;20;-30)represent it in epura together with the points
    B-symmetrical of A to [H];
    C-symmetrical of A to [V];
    D-symmetrical of A to [L];
    E-symmetrical of A to ox;
    F-symmetrical of A to oy;
    G-symmetrical of A to oz.
    so if anyone can help me in this i will be thanks full for him or her a lot ,once again thanks


  9. i studied your notes.
    it was useful for me.
    so,i thank you for kind cooperation

  10. Hi all..
    I am S.Ramanathan, Asst Pro, Dept of Meh Engg, MVSR Engg College, Hyderabad.

    Ihave prepared detailed notes for all solved and unsolved problems of engineering graphics from ND Bhat for most of the topics from scales , conic sections to Isometric projections.

    if any of u want to refer to those notes for clear understanding, please do feel free to get in touch with me.

    i am also available at

  11. dear sir
    please give some examples with this.

  12. Que. The front view of a 125mm long line PQ measured 75mm and it’s top view measures 100mm.It’s end Q and the midpoint M are in the first quadrant ,M being the 20mm from both the plane .Draw the projection of line PQ ?


    sir can u give me the whole engineering drawing ppt file for BE(RGPV SYLLABUS) ……………

  14. say me answer for line midpoint 35mm above hp 50mm below hp inclined at 40 degree to hp and 50 degree to vp
    whether final top view and final front view will it be perpendicular line to reference line or final top view and final front view will it be at some inclination to reference line

  15. sir please send me some on projection of plane and solid

  16. i think the upper projection should be inclined with same slope of the given true length

  17. The front view of a 125mm long line PQ measures 75mm and its top view measures 100mm. Its end Q and mid-point M are in the first quadrant, M being 20 mm from both the planes. Draw the projections of the line PQ.

  18. Sr please solve my problem.
    I am a polytechnic student. 2nd sem

  19. The projections of a line measures 80mmin the top viewand 70 mminthe front view. The mid point of theline is 45 mmin front ofVPand 35 mm above HP. One endis 10 mmin front of VP andnearer to it. The other end is nearer to HP. Drawthe projections of the line. Findthe true lengthand true inclinations.

    pls pls urgently i need answer for this help me nw pls urgent pls

  20. A line AB 100mm long is inclined at 45°to HP and 30°to VP its mid point 50mm above HP and 55mm in front of VP draw that projection

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