Friday, June 23, 2006

[PRMAN]Curve: Segments and nvertices

Linear, nonperiodic: segments = nvertices -1;
Linear, periodic: segments = nvertices;
Cubic, nonperiodic: segments = (nvertices-4)/step +1;
Cubic, periodic: segments = nvertices/step;

Friday, June 16, 2006

[PRMAN]Basis


RtBasis spline = {
{ -1/6.0, 0.5, -0.5, 1/6.0},
{ 0.5, -1, 0.5, 0},
{ -0.5, 0, 0.5, 0},
{ 1/6.0, 2/3.0, 1/6.0, 0}
};


RtBasis hermite = {
{ 2, -2, 1, 1 },
{ -3, 3, -2, -1 },
{ 0, 0, 1, 0 },
{ 1, 0, 0, 0 }
};

RtBasis bezier = {
{ -1, 3, -3, 1 },
{ 3, -6, 3, 0 },
{ -3, 3, 0, 0 },
{ 1, 0, 0, 0 }
};



RtBasis catmullRom = {
{ -0.5, 1.5, -1.5, 0.5 },
{ 1.0, -2.5, 2.0, -0.5 },
{ -0.5, 0.0, 0.5, 0.0 },
{ 0.0, 1.0, 0.0, 0.0 }
};









BasisStep
RiBezierBasis3
RiBSplineBasis1
RiCatmullRomBasis1
RiHermiteBasis2
RiPowerBasis4

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