Parametric and Continuity Equations Flashcards
Parametric coordinate functions,Each section of spline is described with parametric coordinate functions,write those functions
x=x(u)
y=y(u)
z=z(u)
u1<=u<=u2
What is zero-order Parametric (C0)?
Simply means that the curves meet
x,y and z evaluated at u2 for the first curve section are equal to the values of x,y and z evaluated for the next curve section
First-order Parametric C1
The first parametric derivatives( tangent lines) of the coordinate functions for two successive curve sections are equal at their joining point
Second-order parametric functions(C2)
Both the first and second parametric derivatives of the two curve sections are the same intersection
Three methods for specifying a spline representation.
- We can state the set of boundary conditions that are
imposed on the spline. - We can state the matrix that characterizes the spline.
- We can state the set of blending functions
We can write the boundary conditions in matrix form and solve for the
coefficient matrix C as:
𝐶 = 𝑀𝑠𝑝𝑙𝑖𝑛𝑒. 𝑀𝑔𝑒𝑜m
we can substitute the matrix representation for C into the equation to
obtain
X(u)= 𝑈. 𝑀𝑠𝑝𝑙𝑖𝑛𝑒. 𝑀𝑔𝑒𝑜m
The matrix 𝑀𝑠𝑝𝑙𝑖𝑛𝑒, characterizing a spline representation, sometimes
called the
the basis matrix
what are gk and BFk in the polynomial representation of the parameters of the geometric constraint
gk control point coordinates and slope of the curve
BFk polynomial blending functions