# Solid Modelling MCQ – Set 4

This set of Solid Modelling Multiple Choice Questions & Answers (MCQs) focuses on “Sweep Solids – 2”.

1. What are the types of linear sweep in sweep representations of solid?
a) Transverse and rotational
b) Translational and reverse
c) Translational and rotational
d) Rotational and reverse

Explanation: The linear sweep is divided into translational and rotational sweep for solids. In linear sweep, the path is a linear or circular vector. In translational sweep, a planar two-dimensional point set is described by its boundary and in rotational sweep, the planar two-dimensional point set is rotated about the axis of rotation by a given angle.

2. What is the plane curve used in surface generation for sweep representations called as?
a) Isoparametric curve
b) Profile curve
c) PD curve
d) Hermite cubic curve

Explanation: The plane curve used in surface generation for sweep representations is called as the profile curve. In its various positions around the axis, it creates meridians. By revolving a plane curve around an axis line in its plane, surface of revolution is generated.

3. Which of the following sweep is defined by moving a planar curve along a straight line normal to the plane of the curve in solid modelling?
a) Translational sweep
b) General sweep
c) Rotational sweep
d) Reverse sweep

Explanation: Translational sweep is defined by moving a planar curve along a straight line normal to the plane of the curve, the former generating a surface and the latter a solid. These are the main steps followed to generate a solid by translational sweep representations. Here, only small data set is needed to specify the shape at input.

4. What does hybrid sweep in sweep presentations of solid consist of?
a) Translational and rotational sweep
b) Linear and non-linear sweep
c) Linear and reverse sweep
d) Rotational and reverse sweep

Explanation: In sweep representations, hybrid sweep consists of linear sweep described by linear equation and non-linear sweep described by higher order equations. A hybrid sweep is generated by two or more transformations on a plane curve for the purpose of simultaneous rotation and translation.

5. Who did first describe sweep-modeling schemes based on conventional engineering drawing techniques?
a) Choi and Lee
b) Lossing and Eshleman
c) Newton and Lagrange
d) Martin and Stephenson

Explanation: Choi and Lee describe sweep-modeling schemes based on conventional engineering drawing techniques in 1990. They addressed parallel and rotational sweeping, spined sweeping and synchronized sweeping and showed that variety of surface shapes can be defined by specifying control curves.

6. Which trigonometric terms are present in the equation of surface of revolution in solid modelling?
a) cotѳ, tanѳ
b) secѳ, cosѳ
c) sinѳ, cosecѳ
d) sinѳ, cosѳ

Explanation: The equation for surface of revolution is given as p (u, ѳ) = x (u) cosѳ + x(u) sinѳ + z(u), so sinѳ and cosѳ are the trigonometric terms present in the equation. Here, z axis is the axis of rotation and the curve is defined in the x, z plane. It represents general curve, elliptic segment, circular arc, etc.

7. What does the unit vector ‘a’ of cubic Hermite curve define in rotational sweeps?
a) Scalar quantity
b) Angle through which curve rotates
c) Direction of the axis of revolution
d) Point through which axis passes

Explanation: In rotational sweeps, the unit vector ‘a’ of cubic Hermite curve defines the direction of the axis of revolution, a vector ‘b’ locating a point through which the axis passes and Ѱ is angle through which curve rotates. The scaler quantities are defined by k0 and k1 for cubic Hermite curve.

8. A six-component curve trajectory of a generator curve of sweep solids has obvious natural extensions.
a) True
b) False

Explanation: A six-component curve trajectory used to control the movement of generator curve of sweep solids has obvious natural extensions. For example, user could add three more components to yield scale factors to apply to the generator curve which results in expanding or contracting it, and coordinating it with the motions imposed by the PD curve.

Sanfoundry Global Education & Learning Series – Solid Modelling.