Computer Graphics Questions and Answers Part-25

1. Which of the following condition is fulfilled if a circle is completely outside the viewing window?
a) Xc + R = XLEFT
b) Xc + R > XLEFT
c) Xc + XLEFT < R
d) Xc + R < XLEFT

Answer: d
Explanation: The condition that is fulfilled if a circle is completely outside the viewing window is Xc + R < XLEFT. Where, Xc denotes the position of circles centre on the x axis, R is the radius of circle and Xleft is the position of the left most edge of the viewing window on x axis.

2. Which of the following set of conditions is fulfilled if a circle is completely outside the viewing window?
a) Yc – R < Ytop
Yc + R > Ybottom
b) Yc – R > Ytop
Yc + R < Ybottom
c) Yc – R < Ytop
Yc + R < Ybottom
d) Yc – R > Ytop
Yc + R > Ybottom

Answer: b
Explanation: The set of conditions that is fulfilled if a circle is completely outside the viewing window is –
Yc – R > Ytop : This condition is fulfilled if a circle is completely outside and above the viewing window.
Yc + R < Ybottom : This condition is fulfilled if a circle is completely outside and below the viewing window.
Here, Yc is the position of centre of circle on y axis. R is the radius of the circle. Ytop and Ybottom is the position of the top and bottom edge of the viewing window on the y axis respectively,

3. Which of the following is used to adjust the shape of Bezier curve?
a) Control points
b) End points
c) Knots
d) Convex Hull

Answer: a
Explanation: The control points are used to adjust the shape of a Bezier curve. A Bezier curve is always determined by its control points which are denoted by P0 to Pn, where n is the degree of curve which tells the shape of the curve. The first and last control points of a Bezier curve are its endpoints.

4. Which of the following curve is formed with polynomial sections satisfying specified continuity conditions?
a) Bezier Curve
b) Spline Curve
c) Both Bezier and Spline Curves
d) Neither Bezier nor Spline Curve

Answer: b
Explanation: A Spline Curve is formed with polynomial sections satisfying continuity conditions at the boundary of the pieces. We specify a spline curve by giving a set of control points which indicates the general shape of the curve.

5. A hull is a line that connects the control points of a curve.
a) True
b) False

Answer: a
Explanation: A hull is a line that connects all the control points of a curve. The shape of the curve is always inside the shape of the hull. In geometry, the convex hull or convex envelope of a shape is the smallest convex set that contains it.

6. Which of the following clipping process handles the clipping of strings?
a) Curve Clipping
b) Shape Clipping
c) Exterior Clipping
d) Text Clipping

Answer: d
Explanation: The process that handles the clipping of strings is Text Clipping. It is the process that decides which part of the string is to be kept based on their position in the view window. There are different types of Text Clippings like all or none character clipping, all or none string clipping etc.

7. In which of the following text clipping method do we only include the strings that are entirely inside the view window?
a) All or none string clipping
b) All or none character clipping
c) Text clipping
d) We don’t consider the strings that are inside the view window

Answer: a
Explanation: The text clipping method that only include the strings that are entirely inside the view window is all or none string clipping. In this method if the whole string is inside the view window then only the string is saved otherwise it is discarded.

8. How many axes does a three-dimensional graphics consists of?
a) One axis
b) Two axes
c) Three axes
d) Six axes

Answer: c
Explanation: A three-dimensional graphics consists of three axes namely the x axis, the y axis and the z axis. These axes simulate the length, width and height of a 3-dimensional object.

9. Which of the following is the most commonly used boundary representation for a 3-D graphics object?
a) Data polygon
b) Surface polygon
c) System polygon
d) Volume polygon

Answer: b
Explanation: Surface polygon is the most commonly used boundary representation for a 3-D graphics object. The object’s interior is enclosed by this surface polygon. In this method of representation, set of polygons are stored for description of the object.

10. A three-dimensional object can be represented using which of the following representation?
a) Equation
b) Function
c) Point
d) Polygon

Answer: a
Explanation: A three-dimensional object can be represented by using an equation representation. The equation for a 3-dimensional object contains 3 variables x, y and z and 4 coefficients A, B, C and D.