1. What is Surface rendering in Visualization?
☛ Lightening conditions in the screen
☛ Assigned characteristics
☛ Degree of transparency
☛ How rough or smooth the surfaces are to be
☛ Exploded and cutaway views
☛ Three dimensional and stereoscopic views
2. Explain the steps involved in 3D transformation?
☷ Modeling Transformation
☷ Viewing Transformation
☷ Projection Transformation
☷ Workstation Transformation
3. What is Depth CUEING in Visualization?
Basic problem for visualization techniques is called depth cueing.
Some 3D objects are without depth information visible line and surface identification To highlight the visible lines display visible lines as dashed lines removing the invisible lines.
4. Explain informational visualization?
Information visualization concentrates on the use of computer-supported tools to explore large amount of abstract data. The term "information visualization" was originally coined by the User Interface Research Group at Xerox PARC and included Dr. Jock Mackinlay. Practical application of information visualization in computer programs involves selecting, transforming and representing abstract data in a form that facilitates human interaction for exploration and understanding. Important aspects of information visualization are dynamics of visual representation and the interactivity. Strong techniques enable the user to modify the visualization in real-time, thus affording unparalleled perception of patterns and structural relations in the abstract data in question.
Basically, packages designed for graphics programming contain functions for setting primitives, attributes, and parameters for various graphics operations such as viewing and transformations. Packages designed for applications allow a user to create scenes in terms of the particular application, rather than in terms of graphics functions.
6. Which major components (hardware and software) are needed for computer graphics?
Besides the basic computer, some special devices and software may be required especially for computer graphics. For hardware, a special high-resolution, color monitor is often demanded and some input tools, e.g. mouse and joy-sticker, and hard-copy devices, e.g. high-resolution color printer, may be required. For software, some special purpose utilities (device-dependent and device-independent) are needed for handling processing in computer graphics.
7. What is Ellipse generating Algorithm in Visualization?
Algorithm
Step 1:Input radius rx, ry and ellipse center(Xc, Yc)and obtain the first
point on the circumference of a circle centered on the origin as
(X0, Y0) = (0, ry)
Step 2: Calculate the initial values of the decision parameter in region 1 as
P10 = ry
2 - rx
2 ry + 1/4 rx
2
Step 3: At each position starting at Xk position in region 1,starting at k = 0,
perform the following test:
If Pk < 0, the next point to plot is (Xk+1, Yk) and
P1k+1 = P1k+2 ry
2Xk+1 + ry
2
Otherwise the next point is (Xk+1, Yk-1) and
P1k+1 = P1k+2 ry
2Xk+1 - 2ry
2 Yk+1 + ry
2
Step 4: Calculate the initial values of the decision parameter in region 2 as
P20 = ry
2 (X0+1/2)2+ rx
2 (Y0 - 1)2- rx
2 ry
2
Step 5: At each position starting at Yk position in region 2,starting at k = 0,
perform the following test:
If Pk > 0, the next point to plot is (Xk, Yk-1) and
22
P2k+1 = P2k - 2 ry
2Yk+1 + rx
2
Otherwise the next point is (Xk+1, Yk-1) and
P2k+1 = P2k - 2 ry
2Yk+1 - 2rx
2 Yk+1 + rx
2
Step 6: Determine symmetry points in the other three octants
Step 7: Move each pixel position(X, Y) onto the circular path centred on
(Xc, Yc) and plot the coordinate values as
X = X + Xc Y = Y + Yc
Step 8: Repeat steps for region 1 until 2 ry
2X>=2 ry
2Y
8. What is Depth sorting method in Visualization?
Both image and object space operations
Perform the basic function
Surface are sorted in order of decreasing depth
Surface are scan converted in order, starting with the surface of greatest depth
Often referred as painters algorithm
Test listed in the order of increasing difficulty
Surface do not overlap
Projections of the two surfaces on to the view plane do not overlap
9. Explain the advantages of electrostatic plotters?
❁ They are faster than pen plotters and very high quality printers.
❁ Recent electrostatic plotters include a scan-conversion capability.
❁ Color electrostatic plotters are available. They make multiple passes over the paper to plot color pictures.
10. What is pixel phasing in Visualization?
Pixel phasing is an antialiasing technique, stair steps are smoothed out by moving the electron beam to more nearly approximate positions specified by the object geometry.
