**END TERM EXAMINATION**

DECEMBER 2015

BCA (Vth SEMESTER)

## COMPUTER GRAPHICS (BCA-305)

**Time**: 3 Hrs

**MM**: 75

**Note**: Attempt any five questions including Q No. 1 which is compulsory. Select one question from each unit.

**Q1: Explain any five of the following**

(a) The role of Video Controller in Raster Display Systems

(b) Conceptual framework for interactive graphics.

(c) Matrix Representation of 3D scaling

(d) Transformation as a change in a coordinate system.

(e) Polygon mesh

(f) Octree

**UNIT-1****Q2**:

(a) What do you mean by scan conversion? Derive the equation for scan converting a line using Breshnam's line drawing algorithm.

(b) Differentiate between Random Scan and Raster Scan. Explain random scan display processor with suitable diagram. (⚓ See Answer)

**Q3**:

(a) What is clipping? Explain Cohen-Sutherland line clipping algorithm.

(b) Let R be the rectangular window whose lower left-hand corner is at L(-3, 1) and upper right hand corner is at (2,6). Find the end point codes for the following points according to Cohen Sutherland algorithm of the line clipping:

A(-4,2) B(-1, 7) C(-1, 5) D(3,8) E(-2, 3) F(1,2) G(1,-2)

H(3,3) I(-4, 7) J(-2, 10)

__UNIT-II__**Q4**:

(a) Find the general form of transformation N which maps a rectangular window with the extent Wxmin to Wxmax in x direction and Wymin to Wymax in y direction on a rectangular viewport with x extent vxmin to vxmax and y extent vymin to vymax.

(b) Explain the transformation matrices for various 2D transformation in homogeneous coordinates.

**Q5**:

(a) Find the complete viewing transformation that maps a window in a world co-ordinates with x extent 1 to 10 and y extent 1 to 10 on to a viewport with x extent ¼ to ¾ and y extent 0 to ½ in normalized device space and then maps to a window with x extent ¼ to ½ and y extent ¼ to ½ in the normalized device space, into a viewport with x extent 1 to 10 y extent 1 to 10 on the physical display device.

(b) Find the normalised transformation N which uses the rectangle A(1,1), B(5,3), C(4,5) and D(0,3) as a window and a normalised device screen as a viewport.

__UNIT-III__**Q6**:

(b) State and prove a property of Bezier Curve with four control points.

**Q7**:

(a) Explain how Bezier curves are represented parametrically. Consider a Bezier curve having control points P1(20,0), P2(0, 20), P3(80, 40), P4(40, 0)

(b) What is CSG? Discuss various user interfaces for solid modelling.

__UNIT-IV__**Q8**:

(a) What do you mean by hidden surfaces? Discuss Z buffer method for removing hidden surfaces.

(b) Define projection. Differentiate between parallel and perspective projection with suitable examples. (ðŸ˜ŒSee answer)

**Q9**:

(a) "Hidden surfaces should be removed" why? Discuss Painter's algorithm for hidden surfaces examples.

(b) Define orthographic projection. Discuss different applications of parallel and perspective projections.

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