Determines how far an indirect ray can travel before it is terminated. In the case of a ray being terminated due to the indirect range value, it is assumed that the ray would eventually hit the environment background so this value is returned to the shading engine. This is a useful way to optimize render times. Reducing the indirect range generally improves render speed. However, setting this value too low creates unnatural lighting effects as many rays that otherwise would have ultimately hit a geometric surface resulting a shadow can get cut off early and illuminate the surface with the backdrop color rather than shading it with the surrounding geometry.