Bézier patch

Bézier patch (bzrPtch)

key: bzrPtch

type: SCiiC

string: object name.
mat'l: object materialindex.
nPointsU, nPointsV: number of control points in U and V directions, respectively.
C : vertex list: must have nPointsU*nPointsV points.

Description

A four-sided tensor-product Bézier patch of arbitrary degree

Conventions

The first control point is at U=0, V=0; the end of the first row is U=1, V=0. The last control point is at U=1, V=1.
At the moment, patches are restricted to equal degree in U and V:
If texture vertices are given, they must correspond 1:1 to the
Texture coordinates will be linearly interpolated in UV space.

Examples

A cubic patch using default texture coordinates (i.e. the natural parametrization of the patch).

bzrPtch "curved-patch"
   mtrlNm "lambert1" end
   4 4
   vrtxPstn
      -3.0 -3.0 0.0
      -1.0 -3.0 1.0
       1.0 -3.0 1.0
       3.0 -3.0 0.0

      -3.0 -1.0 1.0
      -1.0 -1.0 2.0
       1.0 -1.0 2.0
       3.0 -1.0 1.0

      -3.0  1.0 1.0
      -1.0  1.0 2.0
       1.0  1.0 2.0
       3.0  1.0 1.0

      -3.0  3.0 0.0
      -1.0  3.0 1.0
       1.0  3.0 1.0
       3.0  3.0 0.0
   end
end