Explicit representation of geometry - curves and surfaces

  • Point cloud: list of points (x, y, z)
    turns the point cloud into a polygonal surface, which can be output in the computer
  • Polygonal mesh: Polygon Mesh
    is split into small triangles
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  • Bezier curve
    defines the curve as long as it meets the starting and ending points, P1 and P2 determine which direction it will bend
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  • The de Casteljau algorithm
    defines a time t ranging from 0 to 1,
    finds the time t interpolation between (b0, b1), (b1, b2) respectively, and
    then calculates the time t interpolation between these two points. Get the time t interpolation from b0 to b2
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    How to calculate multiple points?
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    Use recursion to gradually reduce the size of the operation
  • The Bernstein polynomial
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    is actually its own nth-order expansion.
    Example:
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    Note: The Bezier curve property is mostly used for affine transformation, and it does not take effect for projection
  • Convex hull properties:
    the Bezier curve will not exceed the blue range
    , similar to wrapping a rubber band on several nails:
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  • (Piecewise) Segment-by-segment Bezier curve
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    Form a point set of four points by dragging points to generate a smooth curve
  • C0 and C1 are continuous
    C0: The end point is geometrically continuous
    C1: The left and right points form a straight line with equal proportions
    Example:
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  • Bezier surface
    Similar to Bezier curve, expand four points to 16 points to represent a surface. Apply Bezier curve
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    on two planes
    respectively:
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Origin blog.csdn.net/KamikazePilot/article/details/129948919