Distant lights emit uniform parallel light rays in one direction only. The intensity of a distant light is uniform at all points in space. A distant light is controlled simply by setting its direction vector. Since these lights can not be modeled with physical accuracy, it is recommened that these lights are not used with photometric lighting units
The following code shows how to set up a distant light pointing down onto the XY-plane:
// To setup a distant light AcDbLight distantLight; distantLight.setLightType(AcGiDrawable::kDistantLight); distantLight.setLightDirection(AcGePoint3d(0,0,5));