5.2. Bezier (element)

5.2.1. Attributes

5.2.2. Description

This element defines a three- of four-point Bezier curve. The integer value of the size attribute defines the number of control points of the Bezier curve. In the current version, the number of control points must be 3 or 4.

The string value of the location attribute is used to distinguish between the multiple curves that can be associated with a geometric primitive that contain a Bezier curve, such as patch, wave, revolution, wall, or house.

The float values of the x1, y1, z1, x2, y2, z2, x3, y3, z3, x4, y4, and z4 attributes define the coordinates of the three or four control points of the Bezier curve (see figure Figure 5-1). The last three coordinates are ignored in the case of three control points.

The float values of the n_x, n_y, and n_z attributes define the coordinates of a normal vector. The normal vector is used to draw the shape of the Bezier curve when rendering a path media object: the curve is transformed into a surface according to figure Figure 5-2. In this figure, w is the float value of the width attribute in the path element.

The float value of the length attribute defines the length of the curve and avoids automatic computation of the curve length in path-transformations.

5.2.3. Expected children

None.

5.2.4. Example

The example below defines a 4-point Bezier with (1,0,0) as normal vector:

<bezier size="4" location="out"
         x1="0.10" y1="0.20" z1="0.00" 
         x2="0.10" y2="0.20" z2="0.00" 
         x3="0.10" y3="0.10" z3="0.00" 
         x4="0.10" y4="0.00" z4="0.00"  
         n_x="1.0" n_y="0.0" n_z="0.0" />