CAS or Create-A-Sim is an editor included in The Sims 4 so that you can create, edit and customize your sims. It lets you create custom characters that look like your family, friends, celebrities, or even just characters from your imagination. In Sims 3 you had to move different sliders to manipulate their features. Now it has all been made much easier since you can edit your sims by clicking on their bodies and faces, dragging their body parts to make them bigger or smaller, or tugging them up or down to make them taller or shorter. Even fine features like eye angles, cheek bones, and lip shapes are all included.
The CAS editor allows you to do several things: