First you can see Easy 3D Objects of a type Dummy cube in Tree of objects. It is invisible object intended for grouping of other objects.

Element of the tree can be parent or child depending on its position. Objects Easy 3D Objects, Cube, Frustum, Space text, Sprite, Disk, Sphere, Annulus are parents in example of the tree. Object Cone is child of the parent Frustum. Objects Plane and Cylinder are children of the parent Disk. Objects Torus, Arrow line and Mirror are children of the parent Annulus. At the same time child Arrow line is the parent for Mirror.

Parent and its children form group of objects. Position of coordinate axes and angle of inclination of objects in group (children) are defined relative to coordinate axes of parent (like a container for other objects). If you move object, which is parent, then its children move together with it. At the same time each object, which is a child, can move on its own path.

You can:

• add parent or its child to the tree;
  
• delete selected object from the tree;
  
• edit selected object in the tree;
  
• show / hide selected object from the tree on Image Panel;
  
• move up or move down selected object in the tree;
  Note: you can drag any object in the tree with pressed left mouse button and fasten it to necessary object in the tree.