Flatten reference
Flatten moves the selected control points to a single plane.
Design > Form > Modify > Flatten 
Flatten affects controls points. Switch to box mode to see the results.
Direction
Select the method to move points.
| Direction | Definition | Minimum Number of Vertices Per Surface |
|---|---|---|
| Fit | Uses a best fit plane. | 4 |
| Select Plane | Enables the selection of a plane to flatten all control points to. | 1 |
| Select Parallel Plane | Enables the selection of a plane moves control points to a parallel plane. | 2 |
Plane
Select the plane for plane and parallel plane flatten operations.
T-Spline Vertices
Enables the selection of vertices or control points to flatten.
Flatten Type
Select a flatten type.
| Flatten Type | Definition |
|---|---|
| Control Points | Lets you move control points. |
| Surface Points | Lets you move surface points. |