Conversions Between Representations
A wide variety of CAD systems are in use today. The mathematical forms of the curve and surface entities within such systems show a similar diversity. This can lead to two types of problem when considering the transfer of such data between two dissimilar systems. First, there may be a basic incompatibilty in the curve and surface description employed, e.g the sending system might use rational polynomials while the receiving system may only support non-rational forms of a specified degree. Second, the two systems may employ curve and surface entities based on the same underlying building blocks, in particular parametric polynomials of a given degree, but differ in the actual representation used. The first of these problems requires effective approximation of the sending system form to suit that required by the receiving one and is expanded on in chapters 5 and 6. The second problem can in principle be solved by an exact conversion between the two representations involved. We shall be concerned with the solution to the second problem here.
KeywordsControl Point Surface Patch Curve Segment Bezier Curve Bezier Surface
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