Helix Spline

Use Helix to create open flat or 3D helices or spirals.

• Create panel > (Shapes) > Splines > Object Type rollout > Helix
• Standard menu: Create menu > Shapes > Helix
• Enhanced menu: Objects menu > Shapes > Helix

Examples of helices

Note: Unlike other Spline objects, the Helix's segments are set to the Line type by default. This means that if you convert the object to an editable spline and then convert its vertices to Bezier type, it's not possible to edit the vertices by moving the Bezier handles. To do so, first convert any or all of the helix's segments to curves by selecting them, right-clicking, and choosing Curve from the Tools 1 quadrant of the quad menu.

Tip: While creating a Helix spline, you can use the mouse to pan and orbit the viewport between steps. To pan the viewport, drag with the middle mouse button or scroll the mouse wheel. To orbit the viewport, hold down Alt and drag with the middle mouse button or scroll the mouse wheel.

Procedures

To create a helix:

1. Go to the Create panel, click (Shapes), then click the Helix button.
   Note: The default creation method, on the Creation Method rollout, is Center. This means that where you start creating the helix becomes its center point. Alternatively, you can start at the edge.
2. In any viewport, drag and release to set the starting point of the helix and its starting radius (Center method) or diameter (Edge method).
3. Move the mouse vertically and then click to define the height.

   If you create the helix in an orthographic viewport, such as Top or Front, you'll need to view the change in height in another viewport, such as Perspective.

4. Move the mouse and then click to define the end radius.

Interface

Rendering rollout

Most spline-based shapes share these parameters. For details, see Rendering rollout.

Interpolation

The helix differs from other spline-based shapes in that it always uses adaptive interpolation: The number of vertices is determined by the number of turns.

Creation Method rollout

The Helix shape offers the standard creation-method choice: Center or Edge. For an explanation, see Creation Method rollout.

Keyboard Entry rollout

Creates a Helix spline from the keyboard. Use the X/Y/Z settings to specify the center point, and the remaining parameters to specify the radii and height, then click Create. After creating the spline, you can use the Parameters rollout controls to adjust its settings (see following).

Parameters rollout

Once you have created a helix, you can make changes using the following parameters:

Radius 1

Specifies the radius for the Helix start.

Radius 2

Specifies the radius for the Helix end.

Height

Specifies the height of the Helix.

Turns

Specifies the number of turns the Helix makes between its start and end points.

Bias

Forces the turns to accumulate at one end of the helix. Bias has no visible affect when the height is 0.0.

Helical spline varied only by bias settings

• A bias of –1.0 forces the turns toward the start of the helix.
• A bias of 0.0 evenly distributes the turns between the ends.
• A bias of 1.0 forces the turns toward the end of the helix.

CW/CCW

The direction buttons set whether the Helix turns clockwise (CW) or counterclockwise (CCW).