- Select a surface in object selection mode and click Activate Controls
and Greville Points
. The Control Points Filter
and Control Rows Filter
are also valid for the Greville points selection.
Greville points lie on the curve or surface and modify it directly. The number of Greville points is equal to the number of control points. The distance between Greville point and associated control point is normal to the underlying element.
When modifying a Greville point, only the associated control point moves whereas the adjacent Greville points are also moved to maintain a smooth shape.

- Select one or more Greville points.
The robot appears on the first selected Greville point and you can modify the Greville points using the robot.
- Click onto a Greville point row between two Greville points.
The Greville point row is selected and the robot appears on the nearest Greville point. Moving it modifies the Greville point row.

Comparing the results of control point and Greville point modification shows the difference in the modification extent.