Sometime when i do a radiosity render the faces of some objects ‘streak’ the base colour. The objects are generaly modeled with curves and converted to meshes.
My best guess is that the streaking is caused by the light calculations of the “caustics” for lack of a better word. I say caustics because all of the light in a scene is taken into account in a radiosity render. The light off of the black mesh objects may be added to the color of the blue face. I have no solution for this.