===Variety of EM.Cube's Native Object Types===
In [[EM.Cube]], objects are generally categorized into four types: solids, surfaces, curves and special objects. Curves are one-dimensional objects, whose length can be measured. The simplest curve object is a (straight) line. Surfaces are two-dimensional objects whose surface area can be measured. A surface is usually characterized by a number of edges that enclose the object's area. The edges meet at vertices or nodes. The simplest surface object is a rectangle strip, which has four edges and four vertices. Solids are three-dimensional objects whose volume can be measured. A solid is usually characterized by a number of faces that enclose the object's volume. Faces meet at edges and edges meet at vertices or nodes. The simplest solid object is a box, which has six faces, twelve edges and eight vertices. [[EM.Cube]] currently offers two special object types: point and fractal tree. A Point is a dimensionless object that is represented by a set of coordinates (xX,yY,zZ). A fractal tree is a group of recursively scaled self-similar objects. In addition to the standard geometric object types, there are generic curve objects, generic surface objects and generic solid objects. Most external CAD objects are imported as objects of the generic type.
In view of the drawing process and geometrical properties, objects can also be divided into two groups: dimensional objects and nodal objects. A dimensional object is characterized by a local coordinate system (a center and local X-, Y- and Z-axes) and a number of dimensional parameters such as length, width, height, radius, etc. Examples of dimensional objects are box, sphere, rectangular strip, line, helix, etc. A nodal object is characterized by a set of points (nodes). [[EM.Cube]]'s nodal objects include polystrip, polyline, NURBS strip, NURBS curve and polymesh objects.
=== General Drawing Rules ===
By default, when you draw a new object, its property dialog appears at the lower right corner of main Window, and [[EM.Cube]]'s object edit mode is enabled. This means that you can edit the newly drawn object at this time. After the drawing is completed, the mouse cursor changes to its "Normal" arrow shape. Besides the default "Draw & Edit" mode, [[EM.Cube]] provides another drawing modes mode called "Persistent Draw". In this persistent mode, after you complete the drawing of an object, the mouse cursor does not return to "Normal" and stays in the drawing mode. You can continue drawing more objects of the same type as many as you like. Switching the drawing mode is done from the User Preferences Dialog, which can be accessed from '''Edit Preferences...''' In the "Drawing Mode" section of the '''Objects''' tab of this dialog, select the radio button labeled '''Persistent Draw'''. In this mode, you will still see the object's property dialog at the lower left corner of Main Window. You can hide this dialog by unchecking the box labeled '''Display Properties'''.
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