Distant fluxmeter sensor (distantflux)

Distant fluxmeter sensor (distantflux)#







Sensor-to-world transformation matrix.


point or nested shape plugin

Optional. Define the ray target sampling strategy. If this parameter is unset, ray target points are sampled uniformly on the cross section of the scene’s bounding sphere. If a point is passed, rays will target it. If a shape plugin is passed, ray target points will be sampled from its surface.



Optional. Define the ray origin offsetting policy. If this parameter is unset, ray origins are positioned at a far distance from the target. If a value is set, rays are offset by the corresponding distance.

This sensor plugin implements a distant sensor which records the radiative flux density leaving the scene (in W/m², scaled by scene unit length). It covers a hemisphere defined by its to_world parameter and mapped to film coordinates.

The to_world transform is best set using a look_at(). The default orientation covers a hemisphere defined by the [0, 0, 1] direction, and the up film direction is set to [0, 1, 0].

Using a 1x1 film with a stratified sampler is recommended. A different film size can also be used. In that case, the exitant flux is given by the sum of all pixel values.

By default, ray target points are sampled from the cross section of the scene’s bounding sphere. The target parameter can be set to restrict ray target sampling to a specific subregion of the scene. The recorded radiance is averaged over the targeted geometry.

Ray origins are positioned outside of the scene’s geometry.


If this sensor is used with a targeting strategy leading to rays not hitting the scene’s geometry (e.g. default targeting strategy), it will pick up ambient emitter radiance samples (or zero values if no ambient emitter is defined). Therefore, it is almost always preferable to use a nondefault targeting strategy.