<scene version="0.5.0">
	<medium id="medium" type="homogeneous">
		<spectrum name="sigmaS" value="0"/>
		<spectrum name="sigmaA" value="1"/>
	</medium>

	<shape type="disk">
		<transform name="toWorld">
			<translate z="-1"/>
		</transform>
		<bsdf type="diffuse"/>

		<sensor type="irradiancemeter"/>
	</shape>

	<shape type="disk">
		<ref id="medium" name="exterior"/>
	</shape>

	<shape type="disk">
		<boolean name="flipNormals" value="true"/>
		<bsdf type="diffuse"/>

		<transform name="toWorld">
			<translate z="1"/>
		</transform>

		<emitter type="area">
			<spectrum name="radiance" value="1"/>
		</emitter>

		<ref name="exterior" id="medium"/>
	</shape>
</scene>
