The last decade has seen huge progress in terms of light sources, molding technologies and optical simulations.The Rear combination lamps are more and more part of the customer signature, and now even more so the lit appearance.This has driven car manufacturers to define their own criteria for the evaluation of the lit appearance.Therefore the homogeneity was addressed to light designer as a key criteria.What was a simple desire for stylists a couple years ago, to emphasis brand identity and the perceived quality of the appearance, is now an entity to consider by objective requirements to be managed by optical calculations, simulations and measurements.This paper describes on one hand the approach of Automotive Lighting regarding consideration of homogeneity requirements to be applied in the product development process, and on the other hand possible solutions for product optimization.In the field of development process, the investigation of the theoretical meaning of luminance homogeneity and the associated physical units is described.Also ways to simulate luminance homogeneity and ways to evaluate OEM criteria are addressed.Finally, an extensive work driven together with the OEM to define some post processing methodology and assessment criteria to turn it into a SMART requirement is proposed.Regarding the product optimization, an overview of which technical solution gives the best appearance and homogeneity is addressed.The example based on combination of white shell reflector and Opalin diffusion screen is detailed.The final statement will give some perspective of future optimization in the development process and the product:refinement of luminance measurement of post-processing, correlation with simulation, optimized technical solution with light guides, light curtains and other light sources.