The XForm>Helix functions can be used to rotate geometry about a specified axis by a given number of degrees and then translates the geometry by a specified length, parallel to the axis. When using these functions, it will be important to keep the following in mind:

• A positive rotation angle rotates the selected entities counterclockwise from the point of view of the person to whom rotational axis points.

• An axis defined by two positions pointing from the first to the second.

• An axis defined by one position pointing in the direction of the construction view's Z axis.

Using the Functions:

1. Select Helix from the Transform Menu.

2. Select Move, Copy, or Join (see icons below) from the submenu.  

           Helix>Move

           Helix>Copy

           Helix>Join

3. If Join is used, you must indicate whether to use Lines or Splines as joining entities.

4. Select the entities you intend to transform.

5. If either Copy or Join is selected, you must enter the number of copies to be created.

6. Indicate the first point on the rotational axis.

7. Indicate the second point on the rotational axis, or select ACCEPT/OK to make the axis normal to the construction plane.

8. Enter the rotation angle.
   
   Note: degree value x number of copies = degree result. Example: 90 (sample degree value) x 2 (number of copies) = 180 (degrees)

9. Enter the pitch value in number of turns per unit length (the higher the indicated value, the more rotations within a defined unit of length).
   
   The length of the translation vector used on the selected entities is the rotation angle, divided by 360 degrees, divided by the pitch. (a/360) /p.
   
   a = rotation angl
   
   360 = degrees
   
   p = pitch value
   
   Pitch is the distance between the same point on two successive turns of a helix, (distance/turn). XForm-Helix defines Pitch as the number of turns/unit distance, or 1/pitch.

10. The transformation is completed.

Above > An example of Helical>Join, using the Splines option