BT-105 Engineering Graphics - Jun 2022 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
   aConstruct a forward reading vernier scale to read distance correct to decimetre on a map in which the actual distances are reduced in the ratio of $1 : 40000$. The scale should be long enough to measure upto $6\text{ km}$. Mark on the scale a length of $3.34\text{ km}$ and $0.59\text{ km}$.
   How to answer

   • Calculate R.F. = 1/40000
   • Calculate Length of Scale (LOS) = R.F. × Maximum distance = (1/40000) × 6 km = 15 cm
   • Divide the 15 cm line into 6 equal parts to represent kilometres
   • Subdivide the first main scale division and design the vernier scale for decimetre reading
   • Mark the specified distances: 3.34 km and 0.59 km
2. 7 Marks
   bConstruct a hypocycloid, rolling circle $50\text{ mm}$ diameter and directing circle $175\text{ mm}$ diameter. Draw a tangent to it at a point $50\text{ mm}$ from the centre of the directing circle.
   How to answer

   • Calculate the subtended angle $\theta = (r / R) \times 360^\circ = (25 / 87.5) \times 360^\circ = 102.86^\circ$
   • Draw the directing arc with radius $R = 87.5\text{ mm}$ and centre $O$
   • Draw rolling circle of radius $r = 25\text{ mm}$ inside the directing circle
   • Divide the circle and arc into equal number of parts and trace the locus of point P
   • Locate point on curve at $50\text{ mm}$ distance from $O$, draw normal and tangent through this point
3. 7 Marks
   aA line $AB$ of $70\text{ mm}$ long has its end $A$ at $10\text{ mm}$ above H.P and $15\text{ mm}$ in front of V.P. Its front view and top view measure $50\text{ mm}$ and $60\text{ mm}$ respectively. Draw the projections of the line and determine its inclinations with H.P. and V.P.
   How to answer

   • Mark the reference line $xy$, and locate projections of point $A$ ($a'$ at $10\text{ mm}$ above $xy$, $a$ at $15\text{ mm}$ below $xy$)
   • Draw locus of $b'$ and $b$ using given apparent lengths ($50\text{ mm}$ and $60\text{ mm}$) and true length ($70\text{ mm}$)
   • Determine the true inclinations $\theta$ (with H.P.) and $\phi$ (with V.P.) using standard rotating line construction
   • Measure and state the values of angles $\theta$ and $\phi$
4. 7 Marks
   bA line $AB$, $60\text{ mm}$ long has its end $A$ $15\text{ mm}$ above HP and $10\text{ mm}$ in front of V.P. It is inclined at $45^\circ$ to the HP and $30^\circ$ to V.P. Draw it's projections.
   How to answer

   • Draw reference line $xy$ and plot $a'$ ($15\text{ mm}$ above $xy$) and $a$ ($10\text{ mm}$ below $xy$)
   • Draw true length line $a'b_1' = 60\text{ mm}$ at $45^\circ$ to $xy$ to find locus of $b'$
   • Draw true length line $ab_2 = 60\text{ mm}$ at $30^\circ$ to $xy$ to find locus of $b$
   • Project $b_1'$ to top view and rotate to find $b$, then connect $ab$ to get top view
   • Project $b_2$ to front view and rotate to find $b'$, then connect $a'b'$ to get front view
5. 7 Marks
   aDraw the isometric projections of the frustum of a cone of $50\text{ mm}$ base diameter, $25\text{ mm}$ top diameter and $60\text{ mm}$ height.
   How to answer

   • Construct an isometric scale to obtain isometric lengths
   • Draw isometric axes at $30^\circ$ to horizontal
   • Construct bottom rhombus of isometric length corresponding to $50\text{ mm}$ and draw ellipse using 4-centre method
   • Draw vertical axis of isometric height $60\text{ mm}$ and construct top rhombus of isometric length corresponding to $25\text{ mm}$, drawing top ellipse
   • Draw common tangents to top and bottom ellipses to complete the frustum of cone
6. 7 Marks
   bDraw the isometric view of a hexagonal prism having side of base $25\text{ mm}$ and axis $65\text{ mm}$ long resting on its base on HP.
   How to answer

   • Draw the regular hexagon of side $25\text{ mm}$ and enclose it in a rectangle (box)
   • Transfer the enclosing rectangle to the isometric plane (horizontal, at $30^\circ$ to horizontal) using true dimensions
   • Plot the hexagonal corners on the sides of the isometric rectangle
   • Erect vertical edges of height $65\text{ mm}$ from all base corners
   • Join top corners and outline visible and hidden edges properly
7. 7 Marks
   aExplain the layering concept with examples. How is it implemented into CAD software?
   How to answer

   • Definition of layers in CAD as transparent overlays used to organize drawing objects
   • Properties assigned per layer: color, linetype, lineweight, visibility (on/off, freeze/thaw, lock/unlock)
   • Practical examples: separate layers for dimensions, hidden lines, center lines, annotations, and outlines
   • Implementation in CAD software (e.g., LAYER command, Layer Properties Manager dialog, setting current layer)
8. 7 Marks
   bDifferentiate between the first angles and third angles projection.
   How to answer

   • Position of object: between observer and plane (1st angle) vs. plane between observer and object (3rd angle)
   • View arrangement: TV below FV (1st angle) vs. TV above FV (3rd angle)
   • Side view: Right side view drawn on left (1st angle) vs. on right (3rd angle)
   • Projection symbols for both systems (frustum of cone representation)
   • Summary comparison table
9. 7 Marks
   aHow do you specify a plotter for graphics applying?
   How to answer

   • Definition and purpose of a plotter in engineering drawing output
   • Key specifications: Plot size/bed size (A0, A1, etc.), resolution (DPI), plotting speed, pen/inkjet type
   • Interface and compatibility (USB, Ethernet, network protocols, driver support)
   • Software configuration: configuring plotter parameters in CAD (paper size, pen assignments, line width, orientation)
10. 7 Marks
    bWhat is CAD? Name two CAD Softwares. Give advantages and disadvantages of using CAD.
    How to answer

    • Definition of CAD (Computer-Aided Design)
    • Names of two CAD packages (e.g., AutoCAD, SolidWorks, CATIA, Creo)
    • Advantages: high accuracy, ease of editing/modification, faster production, easy storage and transfer, 3D visualization
    • Disadvantages: high initial cost, requires specialized training, software updates/maintenance, computer hardware failure risks
11. 7 Marks
    aExplain the purpose of Zoom command.
    How to answer

    • Purpose of Zoom command: changing magnification/scale of the display area without altering actual drawing dimensions
    • Explanation of common Zoom options: Zoom All, Zoom Extents, Zoom Window, Zoom Dynamic, Zoom Previous, Zoom Realtime
    • Importance during detailing, inspecting complex geometries, and general drawing navigation
12. 7 Marks
    bExplain the method of drawing wireframe models of the following objects. i) Cone ii) Pyramid iii) Prism
    How to answer

    • Definition of wireframe modeling as edge-and-vertex representation of 3D objects
    • Method for Cone: create circular base with segments/vertices, define apex point, connect apex to perimeter points using generator lines
    • Method for Pyramid: create polygonal base (e.g., square), specify apex point in 3D, draw linear edges connecting each base vertex to the apex
    • Method for Prism: draw bottom polygonal base, copy/extrude along the axis vector to create top base, connect corresponding vertices with vertical edges
13. 7 Marks
    aPrepare an ellipse using four different methods in AutoCAD.
    How to answer

    • Method 1: Center method (specifying center point, endpoint of first axis, and distance to other axis)
    • Method 2: Axis, End method (specifying first axis start and end points, followed by other axis distance)
    • Method 3: Elliptical Arc method (creating a partial ellipse with start and end angles)
    • Method 4: Isocircle option (using ELLIPSE command with ISODRAFT/Isocircle mode in isometric drafting)
14. 7 Marks
    bExplain about Building Information Modeling (BIM).
    How to answer

    • Definition of Building Information Modeling (BIM) as an intelligent 3D model-based process
    • Key aspects: geometry, spatial relationships, geographic information, quantities, and material properties
    • Dimensions of BIM (3D modeling, 4D scheduling/time, 5D cost estimating, 6D sustainability, 7D facility management)
    • Benefits: clash detection, improved collaboration, lifecycle data tracking, cost and time reduction
15. 14 Marks
    Write short notes of the following. i) Types of scales ii) Editing commands in CAD iii) Orthographic projection
    How to answer

    • i) Types of scales: Plain scale, Diagonal scale, Vernier scale, Comparative scale, Scale of chords with brief descriptions and uses
    • ii) Editing commands in CAD: Move, Copy, Rotate, Trim, Extend, Fillet, Chamfer, Offset, Mirror, Scale commands with syntax/usage
    • iii) Orthographic projection: Concept of perpendicular projectors, principal planes of projection (HP, VP, PP), 1st and 3rd angle projection methods