From GeoGebra Manual
Redefining objects is a very versatile way to change a construction. Please note that this may also change the order of the construction steps in the Construction Protocol.
Note: The redefined element can only depend on elements defined earlier in the construction order, so you may need to change order of the elements in Construction Protocol.
In GeoGebra, an object may be redefined in different ways:
- Select Move Tool and double click on any object in the Algebra View.
- For free objects an editing field is opened allowing you to directly change the algebraic representation of the object. Hit the Enter key in order to apply these changes.
- For dependent objects the Redefine dialog is opened allowing you to redefine the object.
- Select Move Tool and double click on any object in the Graphics View. This opens the Redefine dialog and allows you to redefine the object.
- Change any object by entering its name and the new definition into the Input Bar.
- Open the Properties Dialog and change the definition of an object on tab Basic.
Fixed objects cannot be redefined. In order to redefine a fixed object, you need to free it first using tab Basic of the Properties Dialog.
You can also redefine existing objects in the Input Bar. For example type
a:Segment[A, B]to redefine
ato be a segment.
Example: In order to place an existing free point A onto an existing line h, you first need to double click on the point A to open the Redefine dialog window. Then change the definition to
Point[h]in the appearing text field and press Enter. To remove point A from this line and make it free again, you need to redefine it to some free coordinates, e.g. (1, 2).
Example: Another example is the conversion of a line h through two points A and B into a segment. Open the Redefine dialog for line h and change