What is the difference between a viewport and model space in AutoCAD?

In AutoCAD, model space is the primary workspace where all drawing and design work takes place. It allows users to create objects at their actual size in a 3D environment. The model space acts as the main canvas for your designs, where every element is created in a real-world scale.

A viewport, on the other hand, is a defined area within paper space that displays a specific view of the model space. This means that it allows you to represent your work as you intend it to appear when printed or finalized. Multiple viewports can be used to show different views or scales of the same model space in a single layout.

Therefore, the correct choice highlights that model space is intended for the actual drawing and construction of models, while a viewport serves as a viewing window into that model space when working in paper space. This distinction is crucial for proper organization and representation of designs in both 2D and 3D applications.