BT-105 Engineering Graphics - Dec 2025 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 7 Marks
   aTo draw a line inclined at $45^{\circ}$, $30^{\circ}$ or $60^{\circ}$ to a given horizontal line from a given point.
   How to answer

   • Use of compass arcs to construct standard angles from horizontal
   • Mark given point and draw horizontal reference line
   • Construction steps for $45^{\circ}$, $30^{\circ}$ and $60^{\circ}$ without protractor
2. 7 Marks
   bWithout using a protractor, draw triangles having following base angles on a 75 mm long line as base: i) $75^{\circ}$ and $15^{\circ}$ ii) $60^{\circ}$ and $75^{\circ}$ iii) $135^{\circ}$ and $15^{\circ}$ iv) $105^{\circ}$ and $45^{\circ}$
   How to answer

   • 75 mm base line as base for all triangles
   • Compass construction of required base angles without protractor
   • Completion of four triangles by intersection of angle arms
3. 7 Marks
   aDiscuss the significance of Engineering Drawing in engineering communication.
   How to answer

   • Engineering drawing as universal language of engineers
   • Role in conveying design intent, dimensions and tolerances
   • Importance in manufacturing, construction and documentation
4. 7 Marks
   bExplain lettering in Engineering Drawing. Discuss different types and rules for good lettering.
   How to answer

   • Definition and purpose of lettering in engineering drawing
   • Types of lettering - single stroke, double stroke, vertical, inclined
   • Rules for good lettering - uniformity, spacing, height, legibility
5. 7 Marks
   aDefine orthographic projection. Describe briefly the method of obtaining an orthographic projection of an object.
   How to answer

   • Definition of orthographic projection and projection planes
   • Principle of parallel projectors perpendicular to plane
   • Method of obtaining front, top and side views
6. 7 Marks
   bA point P is 15 mm above the H.P. and 20 mm in front of the V.P. Another point Q is 25 mm behind the V.P. and 40 mm below the H.P. Draw projections of P and Q keeping the distance between their projectors equal to 90 mm. Draw straight lines joining (i) their top views and (ii) their front views.
   How to answer

   • Locate P 15 mm above XY in front view and 20 mm below XY in top view
   • Locate Q 40 mm below XY in front view and 25 mm above XY in top view with 90 mm between projectors
   • Join top views and join front views with straight lines
7. 7 Marks
   aExplain in detail the principles of isometric projection and the construction of an isometric scale.
   How to answer

   • Principle of isometric projection with 120 degree axes
   • Isometric vs true length and foreshortening
   • Construction of isometric scale using 45 and 30 degree method
8. 7 Marks
   bExplain the construction of isometric views of simple solids such as pyramid, and cone.
   How to answer

   • Box method for pyramid base and apex location
   • Construction of base ellipse and apex for cone in isometric
   • Use of isometric scale for true dimensions
9. 7 Marks
   aA square prism, base 40 mm side and height 65 mm, has its axis inclined at $45^{\circ}$ to the H.P. and has an edge of its base, on the H.P and inclined at $30^{\circ}$ to the V.P. Draw its projections.
   How to answer

   • First stage with base edge on H.P. and axis perpendicular
   • Second stage tilting axis 45 degrees to H.P.
   • Third stage rotating base edge 30 degrees to V.P. and final projections
10. 7 Marks
    bA cylinder, 65 mm diameter and 90 mm long, has its axis parallel to the H.P. and inclined at $30^{\circ}$ to the V.P. It is cut by a vertical section plane in such a way that the true shape of the section is an ellipse having the major axis 75 mm long. Draw its sectional front view and true shape of the section.
    How to answer

    • Draw top and front views with axis parallel to H.P. and 30 degrees to V.P.
    • Locate section plane to give 75 mm major axis ellipse
    • Project sectional front view and draw true shape of section by auxiliary projection
11. 14 Marks
    A pipe 40 mm diameter and 120 mm long (along the axis) is welded to the vertical side of a tank. Show the development of the pipe, if it makes an angle of $60^{\circ}$ with the side to which it is welded, the other end of the pipe making an angle of $30^{\circ}$ with its own axis. Neglect thickness of the pipe.
    How to answer

    • Draw side view of tank and pipe inclined 60 degrees to wall
    • Divide circle into generators and project truncated lengths
    • Develop lateral surface with top edge cut at 30 degrees to axis
12. 7 Marks
    aDraw the isometric view of a square prism, side of the base 20 mm long and the axis 40 mm long, when its axis is (i) vertical and (ii) horizontal.
    How to answer

    • Isometric axes at 30 degrees with vertical for vertical axis case
    • Use isometric scale for 20 mm base and 40 mm axis length
    • Rotate to horizontal axis position for second view
13. 7 Marks
    bDefine Building Information Modelling (BIM). How does a BIM "wall" object differ from two parallel lines in traditional 2D CAD?
    How to answer

    • Definition of BIM as data-rich 3D model with information
    • BIM wall as parametric object with properties
    • Difference from dumb 2D lines - intelligence, quantity, updates
14. 7 Marks
    aWrite the name and sequence of command to create hole in solid.
    How to answer

    • Name of hole-creating command e.g. HOLE / Extrude-Cut / Subtract
    • Sequence: draw profile, select plane, sketch circle, extrude-cut
    • Finish with through / blind parameters
15. 7 Marks
    bMention the use of Insert command and explain it's scale option.
    How to answer

    • Purpose of Insert command to insert blocks / external references
    • Use for reusable symbols and drawings
    • Explanation of scale option to resize on insertion