A 3D configurator enables the user to customize and configure the product according to individual requirements. With a 3D configurator, various options such as colors, materials, sizes, features, etc. can be selected and visualized.
A 3D viewer allows the user to view and rotate the product from different angles to get a comprehensive idea of it. A 3D viewer usually does NOT offer the possibility to customize or configure the product.
With augmented reality (AR), for example, customers can "project" a 3D model of a sofa into their personal living room and see how it would look there without physically holding the actual piece of furniture in their hands.