Track Mode
tracking(moving) in the current view plane. As soon as the Track Mode is activated, a rectangular box surrounding the object projection will appear. This box is called the
Bounding Boxof the object.
forecast box) will be displayed which predicts the future position of the object. By moving the mouse, this position can be altered. When the left mouse button is released, the object will be drawn at the new position and the tracking operation is done. Holding down the Ctrl and / or the Shift key while changing the position of the forecast box will cause the following behaviour:
- Ctrl+mouse movement – object only moves horizontally
- Shift+mouse movement – object only moves vertically
- Ctrl+Shift> + mouse movement – object moves back to original position.
The scaling operation for predefined templates allows isogonal scaling in the initial object coordinate system. Here is a more detailed explanation: in the initial object state (object is not yet rotated) all scaling operations are done with respect to the object origin. So, this point is a scaling operation fixed point. In this state, a mouse movement to the right after initiating the scaling operation leads to a broadening of the object, a mouse movement to the left leads to a curtailment. If the mouse is moved upwards, the object becomes larger, moving the mouse downwards shortens the object. Now think of a rotated object and notice that the object coordinate system is rotated as well. Imagine a 180 degrees rotation about the z-axis, if the object coordinate system was not rotated together with the object, a mouse movement to the right now would increase the size of the object on its left side. As this would be an inconsistency in the user interface, a different concept is used. The object coordinate system is rotated together with the object and the interpretation of the mouse movement is rotated accordingly. Always consider the fact that the object origin is bound to the object, it does not change using the rotation operation. Now, a rotated object shows the following behaviour: if the mouse is moved into the direction which was the former right side
of the object its width will increase. This concept offers a more consistent way of handling rotated objects to be scaled.
- Ctrl key only allows scaling in the 1st object coordinate
- Shift key only allows scaling in the 2nd object coordinate
- Ctrl and Shift keys held down simultaneously allow free scaling in both object coordinates.
Double-clicking the left mouse button leaves the Track Mode and switches to the Rotate Mode.