13. Differentiate between interpolation spline and approximation spline?
When the spline curve passes through all the control points then it is called interpolate. When the curve is not passing through all the control points then that curve is called approximation spline.
14. What do you mean by parabolic splines?
For parabolic splines a parabola is fitted through the first three points p1,p2,p3 of the data array of kot points. Then a second parabolic arc is found to fit the sequence of points p2, p3, p4. This continues in this way until a parabolic arc is found to fit through points pn-2, pn-1 and pn. The final plotted curve is a meshing together of all these parabolic arcs.
15. What is cubic spline?
Cubic splines are a straight forward extension of the concepts underlying parabolic spline. The total curve in this case is a sequence of arcs of cubic rather than parabolic curves 32 Each cubic satisfies :ax+ bx + cx + d
16. What is a Blobby object?
Some objects do not maintain a fixed shape, but change their surface characteristics in certain motions or when in proximity to other objects. That is known as blobby objects. Example – molecular structures, water droplets.
17. Define Octrees?
Hierarchical tree structures called octrees, are used to represent solid objects in some graphics systems. Medical imaging and other applications that require displays of object cross sections commonly use octree representation.
18. Define Projection?
The process of displaying 3D into a 2D display unit is known as projection. The projection transforms 3D objects into a 2D projection plane.
19. What are the steps involved in 3D transformation?
• Modeling Transformation
• Viewing Transformation
• Projection Transformation
• Workstation Transformation
20. What do you mean by view plane?
A view plane is nothing but the film plane in camera which is positioned and oriented for a particular shot of the scene.
21. What is view-plane normal vector?
This normal vector is the direction perpendicular to the view plane and it is called as [DXN DYN DZN]
22. What is view distance?
The view plane normal vector is a directed line segment from the view plane to the view reference point. The length of this directed line segment is referred to as view distance
23. Define projection?
The process of converting the description of objects from world coordinates to viewing coordinates is known as projection
24. What you mean by parallel projection?
Parallel projection is one in which z coordinates is discarded and parallel lines from each vertex on the object are extended until they intersect the view plane.
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