<!-- This file is to illustrate the use of the element ray and constraint ray_from_point_through_point.
     It still has not been run on any DGS, so it may contain bugs. 
	 
	 r is the ray starting at B and passing through C.
	 -->
<construction xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../xml/intergeo.xsd">
	<elements>
		<point id="B">
			<homogeneous_coordinates>
				<double>1.0</double>
				<double>0.0</double>
				<double>1.0</double>
			</homogeneous_coordinates>
		</point>
		<point id="C">
			<homogeneous_coordinates>
				<double>2.0</double>
				<double>1.0</double>
				<double>1.0</double>
			</homogeneous_coordinates>
		</point>
		<ray id="r">
			<homogeneous_coordinates>
				<double>1.0</double>
				<double>0.0</double>
				<double>1.0</double>
			</homogeneous_coordinates>
			<homogeneous_coordinates>
				<double>2.0</double>
				<double>1.0</double>
				<double>1.0</double>
			</homogeneous_coordinates>
		</ray>
	</elements>
	<constraints>
		<free_point>
			<point out="true">B</point>
		</free_point>
		<free_point>
			<point out="true">C</point>
		</free_point>
		<ray_from_point_through_point>
			<ray out="true">r</ray>
			<point>B</point>
			<point>C</point>
		</ray_from_point_through_point>
	</constraints>
</construction>
