When the Global or User-defined (UCS) co-ordinate system is not enough as a predefined system for component directions (Point support, Point-point connection and Line-line connection), a custom local system can be defined. Tree points declare the system and the 4^th point places the new object:

1^st point: system origin,

2^nd point: defines the x’ axis direction,

3^rd point: defines the y’ axis direction.

The z’ axis of the system always perpendicular to the x’y’ plane.

The new system directions are set for all objects till   stops the repetition of object insertion and restarts with another system definition.

Figure: Point support group set by a special local system

Figure: Typical example for special direction (Point support group)