a) What is scale? Classify its different types. What are the main uses of scale?

b) Construct a vernier scale to read meters, decimeters and long enough to measure up to 6 meters when 1 meter is represented by 2.5 centimeters. Find R.F. and show on it a distance of 4.33 meters.

a) What is 3D modeling? Explain types of modeling.

b) Construct a parabola when the distance between focus from the directrix is equal to 60 mm. Draw a tangent and normal at any point on the parabola.

a) A straight line segment is 100 mm long, measures 80 mm in plan and 70 mm in elevation. The middle point M is situated 36 mm above H.P. and 46 mm in front of V.P. Draw the top and front views of the line AB.

b) Name the methods which are employed to determine the length and true inclinations of a straight line.

a) A rectangular plate ABCD measuring 45 mm x 35 mm, has its diagonal AC inclined at $30^\circ$ to the H.P. where as the diagonal BD makes an apparent angle of $45^\circ$ to V.P. Draw its projection.

b) Draw the projections of a pentagonal plane, side 25 mm, resting in the H.P. on one of its edges. The plane of pentagon is inclined at $45^\circ$ to the H.P. and the perpendicular, from the midpoint of the resting edge, makes an angle of $30^\circ$ with the V.P.

A regular tetrahedron edge of base 30 mm, is resting on one of its edges on the horizontal plane. The resting edge makes an angle of $45^\circ$ to V.P. and the face containing the edge makes an angle of $30^\circ$ to H.P. Draw its projections.

A right circular cylinder, base $\phi$54 and axis 75 mm long, with a circular hole of $\phi$30 mm, drilled centrally through it, rests on its base on H.P. A section plane $45^\circ$ to H.P. cuts the axis at a distance of 20 mm from the top end face. Draw the sectional top view and true shape of section.

a) A square prism of 50 mm edge and 65 mm height stands on one of its faces on the H.P. with a vertical face making $45^\circ$ angle with V.P. A horizontal hole of 25 mm diameter is drilled centrally through the prism such that the hole passes through the opposite vertical edges of the cube. Draw the development of the surface of the prism and the hole.

b) A cube of 40 mm side rests centrally on a square block of 60 mm edges and 20 mm thick. Draw the isometric projection of the two objects with the edges of the two blocks mutually parallel to each other.

Write short notes on the following (any two)

i) Editing commands in CAD

ii) Layering concept

iii) Purpose of Zoom command