It is a known fact that in general high-detailed models aren't suitable for real time rendering, so it's often necessary to reduce their complexity in terms of number of polygons and materials. Total Baker is a Texture Baking tool for Unity that allows you to create texture maps for a low-poly model so that it will look like more detailed. For example, look at the following image. The low-poly model on the left has just 16 polygons and one material. Once we apply good texture maps in its material it becomes very similar to the high-poly model on the right, which has about 19k polygons and 5 materials. All these texture maps (diffuse, normal, height, ambient occlusion, metallic) were built using Total Baker.