One of the biggest problems in games is repetitions. Creating new content is a time-consuming task, and when you have to face thousands of enemies, chances are that they will all look the same. A relatively cheap technique to add variations to your models is using a shader that alters its basic geometry. This recipe will show you a technique called normal extrusion, which can be used to create a chubbier or skinnier version of a model, as shown in the following picture with the soldier from the Unity camp demo:
For this recipe, we need to have access to the shader used by the model that you want to alter. Once you have it, we duplicate it so that we can edit it safely. It can be done as follows:
Find the shader your model is using and once selected, duplicate it by pressing Ctrl + D.
Duplicate the original material of the model and assign the cloned shader to it.
Assign the new material to your model, and start editing it.