When modeling, you need to start with a geometric object.
In addition to what is described in this chapter, there are some other ways of getting a geometric object that are described elsewhere:
You can draw polygons as described in Adding and Editing Polygons (Drawing) [Polygon Modeling].
You can draw curves as described in Drawing and Manipulating Curves [Surface and Curve Modeling].
You can generate polygon meshes and NURBS surfaces from curves as described in Generating Objects from Curves, or you can convert curves to polygon meshes as described in Converting Curves to Polygon Meshes [Polygon Modeling].
You can also import 3D objects from other software as described in Importing and Exporting [Data Management].
