As we have seen, the Application toolbar displays three icons that represent the main working modes:
Object mode.
Used to select objects and to apply transformations to selected objects (translate, rotate, scale, mirror, etc.). To select an object, you can click any point of its surface. Object mode can also be selected by toggling the menu command Edit > Toggle object/edit mode.
Edit mode
Used to work on hotSpots. The hotSpots are displayed in blue and allow you to interactively modify object/action parameters by dragging/selecting hotSpots in any view. HotSpots can be associated to any parameter. They can be control points, vertices, isoparametric curves on a surface, the focuses of an ellipse, or anything that can be associated to a parameter. Some can be dragged while others may only be selected.
When you are over a hotSpot, a yellow tab displays its name. In case of a circle, for example, you can modify radius and start/end angles by just clicking the appropriate hotSpots and dragging them. When in Edit mode you cannot select or deselect objects in the views, unless you resort to the browser. Edit mode can also be selected by toggling the menu command Edit > Toggle object/edit mode.
Note: You can quickly toggle from Object mode to Edit mode by pressing Spacebar. Learning to use this shortcut can dramatically improve your workflow.
Group mode
Used to select groups and to apply transformations and/or materials to a group as a whole. If you pick an object that is part of a group, the entire group will be selected. When you are in Group mode you cannot translate an object or a group by clicking and dragging in the view, while it is still possible to apply any transformation by activating the appropriate tool.
Edit objects points mode
Allows to modify the position of the objects control points (for a NURBS primitive) or vertices (for a PolyMesh) even if the object is the result of a Construction Tree.
This would normally be impossible since the objects points positions are determined by the Action that built the object itself. With this editing mode, which compares to the editing of the Actions parameters, it is possible to move these points. What actually happens is that an offset is attached to every moved point. This offset is maintained even if the objects original points are changed by the source Action.
To enable objects points editing, click the icon or use the Alt + Spacebar shortcut.
Remember that this actually switch from Edit objects points to Edit Modeling Tools parameters but to effectively see and manipulate objects points, you must also select Edit mode.
When in Edit objects points mode, the Multi Edit modeling tool is automatically invoked. Transformations can be applied using the standard transformation modeling tools: Translate, Rotate and Scale (to be invoked by clicking their corresponding icons or by using the T, R or S shortcuts, respectively).
The Multi Edit modeling tool panel contains two buttons to remove the editing from the currently selected points (Un-edit selected) and from all the points of the currently selected objects (Un-edit all).
The offset is actually bound only to objects that are the result of an Action. Collapsed objects - objects whose Construction Tree has been collapsed - will have their points moved. This is to avoid useless complications: since these objects have no action behind them, their points can be freely moved. Anyway, all this processing is performed automatically by the program and the user does not have to take into account these special cases.
The fact that an offset is bound to the point must be taken into account when using this editing mode. Moving points of revolution objects (i.e. sphere, circle, lathe) may give unexpected results if the object is, for example, refined (more points added along the circumference) or if Start angle or End angle parameters are changed. The offsets applied are always specified as (X,Y,Z) values added to the source points, not as radial offsets with respect to the circumference on which the object is based.