Home > freetb4matlab > nurbs > nrbcoons.m

# nrbcoons

## SYNOPSIS

function srf = nrbcoons(u1, u2, v1, v2)

## DESCRIPTION

```
NRBCOONS: Construction of a Coons patch.

Calling Sequence:

srf = nrbcoons(ucrv1, ucrv2, vcrv1, vcrv2)

Parameters:

ucrv1    : NURBS curve defining the bottom U direction boundary of
the constructed NURBS surface.

ucrv2    : NURBS curve defining the top U direction boundary of
the constructed NURBS surface.

vcrv1    : NURBS curve defining the bottom V direction boundary of
the constructed NURBS surface.

vcrv2    : NURBS curve defining the top V direction boundary of
the constructed NURBS surface.

srf        : Coons NURBS surface patch.

Description:

Construction of a bilinearly blended Coons surface patch from four NURBS
curves that define the boundary.

The orientation of the four NURBS boundary curves.

^ V direction
|
|     ucrv2
------->--------
|              |
|              |
vcrv1 ^   Surface    ^ vcrv2
|              |
|              |
------->-----------> U direction
ucrv1

Examples:

// Define four NURBS curves and construct a Coons surface patch.
pnts = [ 0.0  3.0  4.5  6.5 8.0 10.0;
0.0  0.0  0.0  0.0 0.0  0.0;
2.0  2.0  7.0  4.0 7.0  9.0];
crv1 = nrbmak(pnts, [0 0 0 1/3 0.5 2/3 1 1 1]);

pnts= [ 0.0  3.0  5.0  8.0 10.0;
10.0 10.0 10.0 10.0 10.0;
3.0  5.0  8.0  6.0 10.0];
crv2 = nrbmak(pnts, [0 0 0 1/3 2/3 1 1 1]);

pnts= [ 0.0 0.0 0.0 0.0;
0.0 3.0 8.0 10.0;
2.0 0.0 5.0 3.0];
crv3 = nrbmak(pnts, [0 0 0 0.5 1 1 1]);

pnts= [ 10.0 10.0 10.0 10.0 10.0;
0.0   3.0  5.0  8.0 10.0;
9.0   7.0  7.0 10.0 10.0];
crv4 = nrbmak(pnts, [0 0 0 0.25 0.75 1 1 1]);

srf = nrbcoons(crv1, crv2, crv3, crv4);
nrbplot(srf,[20 20],220,45);```

## CROSS-REFERENCE INFORMATION

This function calls:
This function is called by:
• democoons Construction of a bilinearly blended Coons surface

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