#### 12.1 Useful macros: add functionality to Archimedes

Letīs assume you often need the perpendicular bisector plane of two points. This can be easily
constructed:

- start with points P1 and P2
- construct the midpoint (mark P1 and P2 and press the point-button)
- construct the vector from the midpoint to one of the other points
- construct the plane by marking the midpoint and the vector.

Using P1 and P2 as a basis, the other objects were constructed. If you select those points
and choose ’Macro - mark as given’ these objects are taken as the base-objects of the
macro.

Save the macro (as ’MacroBisectorPlane.geosave, for instance) so that you can use it later
on.

If you start a new construction and select two points, you can now use ’Macro - play’ and select
the macro you have just made. The bisector appears - but the midpoint and the vector appear,
too.

If you do not want supplementary objects to appear in the scene, you will have to hide them in
the macro.