Linear Light sources with Normalized Surface Intensity

Comment: In contrast to a cylindrical light source, which is of finite extend, a linear light source is one dimensional and its only dimension is length. For realistic modelling, these unphysical objects (the intensity increases to infinity near to the light source) these objects are embedded within an cylindrical object. These objectes are enlightened from inside and seem to 'glow'. The intensity is maximal along the light axis and at the symmetry center. Therefore the surrounding cylinder is brighter in its center than at the edges. This might be compensated by normalization of the intensity to have a constant value at the surface of the cylinder. Now the brightness of the cylinder is constant on its surface, but the light coming from it seems to be more intense at the cylinder's edges than in the symmetry plane. This is the effect of a linear light source embedded in a cylinder which shadows most of the light along its mantle and lets the interior light source shine mainly through its end areas. This effect is also prominent if seen from an upper location.