## CG LAB EXAM VIVA QUESTIONS AND ANSWERS.

- Name any three font editing tools.

ResEdit, FONTographer - Differentiate serif and sans serif fonts.

Give oneexampleSerif fonts has a little decoration at the end of the letter,but serif font has not. Times, new century schoolbook is theexamples of serif fonts. Arial, potima are examples for sansserif fonts - Distinguish between window port & view port?

A portion of a picture that is to be displayed by a window isknown as window port. The display area of the partselected or the form in which the selected part is viewed isknown as view port. - Define clipping?

Clipping is the method of cutting a graphics display toneatly fit a predefined graphics region or the view port - What is the need of homogeneous coordinates?

To perform more than one transformation at a time, usehomogeneouscoordinates or matrixes. They reduceunwanted calculations intermediate steps saves time andmemory and produce a sequence of transformations - Distinguish between uniform scaling and differentialscaling?

When the scaling factors sx and sy are assigned to thesame value, a uniform scaling is produced that maintainsrelative object proportions. Unequal values for sx and syresult in a differential scaling that is often used in designapplication - What is fixed point scaling?

The location of a scaled object can be controlled by aposition called the fixed point that is to remain unchangedafter the scaling transformation. - What is Bezier Basis Function?

Bezier Basis functions are a set of polynomials, which canbe used instead of the primitive polynomial basis, and havesome useful properties for interactive curve design - What is surface patchA single surface element can be defined as the surfacetraced out as two parameters (u, v) take all possible valuesbetween 0 and 1 in a two-parameter representation. Such asingle surface element is known as a surface patch
- Define B-Spline curve?

A B-Spline curve is a set of piecewise(usually cubic)polynomial segments that pass close to a set of controlpoints. However the curve does not pass through thesecontrol points, it only passes close to them - What is a spline?

To produce a smooth curve through a designed set ofpoints, a flexible strip called spline is used. Such a splinecurve can be mathematically described with a piecewisecubic polynomial function whose first and secondderivatives are continuous across various curve section. - What are the different ways of specifying spline curve?.

Using a set of boundary conditions that are imposed onthe spline.. Using the state matrix that characteristics the spline. Using a set of blending functions that calculate thepositions along the curve path by specifying combination ofgeometric constraints on the curve - What are the important properties of Bezier Curve?.

It needs only four control points. It always passes through the first and last control points. The curve lies entirely within the convex half formed byfour control points. - Define Projection?

The process of displaying 3D into a 2D display unit isknown as projection. The projection transforms 3D objectsinto a 2D projection plane - What are the steps involved in 3D transformation?.

Modeling Transformation. Viewing Transformation. Projection TransformationWorkstation Transformation - What do you mean by view plane?

A view plane is nothing but the film plane in camera whichis positioned and oriented for a particular shot of the scene. - Define projection?

The process of converting the description of objects fromworld coordinates to viewing coordinates is known asprojection - What you mean by parallel projection?

Parallel projection is one in which z coordinates is discardedand parallel lines from each vertex on the object areextended until they intersect the view plane - What do you mean by Perspective projection?

Perspective projection is one in which the lines of projectionare not parallel. Instead, they all converge at a single point. - What is Projection reference point?

In Perspective projection, the lines of projection are notparallel. Instead, they all converge at a single point. - Define computer graphics animation?

Computer graphics animation is the use of computergraphics equipment where the graphics outputpresentation dynamically changes in real time. This isoften also called real time animation. - What is tweening?

It is the process, which is applicable to animation objectsdefined by a sequence of points, and that change shapefrom frame to frame. - Define frame?

One of the shape photographs that a film or video is madeof is known as frame. - What is key frame?

One of the shape photographs that a film or video is madeof the shape of an object is known initially and for a smallno of other frames called keyframe. - Define Random scan/Raster scan displays?

Random scan is a method in which the display is made bythe electronic beam which is directed only to the points orpart of the screen where the picture is to bedrawn.The Raster scan system is a scanning technique in whichthe electrons sweep from top to bottom and from left toright. The intensity is turned on or off to light andunlight the pixel.

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