In previous versions Vectorworks, if you want to apply a texture to represent a material, you would have to assign a texture. Assigning this texture would not help with hidden rendering or with the plan view of the object. We would often use a class to control the texture on all objects that had the same material. This often made it difficult when you wanted to control the visibility of an object separate from its material.
For several years, users have been asking for an ability to attach a material rather than use classes to control textures. In response, Vectorworks have created the ability to add or to assign materials to objects. These materials do not require a class to control them. All objects that have the same material assigned will appear the same. If you update that material all of those objects will update as well. Materials are designed to control the texture in a rendered view.