Fade in Fade out in unity

i have 3d model and i want to do fade in fade out on model. suppose i will go to model 1 to model 2 and it will go fade in or fade out. can anyone help me about this topic

You can use the Transparent/Diffuse shader, and script it using Material.color and Color.lerp. The material.color changes this objects material instance, while the Color.Lerp makes a smooth transition between opaque and transparent.