This function provides the capability to twist solids, Surfaces and wireframe entities. This is ideal for modeling parts that are manufactured in a flat condition then twisted into final shape. Keep in mind that when twisting, one part stays fixed in place, while the other side of the part rotates along with the twist. The part of the body (if any) before the starting point of the twist axis is the side that remains fixed. The part of the body (if any) after the twist's ending point will be rotated about the axis by the amount of the twist angle.

The region of twist is defined by two points, which you must indicate. These two points define a line that serves two purposes. First, it defines the axis about which the twisting occurs. Secondly, it defines the extents of the twist region. Perpendicular planes at each end of the line are intersected with the body being twisted, and only the area between the planes will be modified.

 

Using the Function:

The required steps might change depending upon what settings are chosen in the dialog box for the function.

1. Select Twist from the Modify>Warp submenu.

2. The Twist dialog box appears, from which you are able to specify a twist angle, the entity types to twist, and the desired continuity. These settings are explained below in detail. Once you have configured the dialog settings, select OK to accept any changes that had been made.

3. Select the body(s) to twist.

4. Indicate the start point of the twist axis.

5. Indicate the end point of the twist axis.

6. The twist is performed per the specifications made.

Dialog Options:

Angle

Enter a twist angle in the editable field. The twist angle is set to 180 degrees by default. There is no limit to the angle of twist. A positive twist angle indicates the direction of the twist, but you may specify a negative angle if you want to twist in the opposite direction. The two points selected to define the axis of twist also indicate the direction of the "Z" axis. Use the right-hand rule to determine the positive direction of twist.

Type of Entities to Twist

Indicate the entity types you intend to twist.

• Solid or Surfaces - When selected, you will be allowed to twist either solids or Surfaces.

• Wires - When selected, you will be allowed to twist Wireframe entity types.

Desired Continuity between Twisted and Untwisted Sections

Specify the desired continuity from the three available settings: G0, G1, or G2.

• G0 – Positional Continuity - This ensures that the edge at the end of the untwisted section and the edge at the beginning of the twist meet.

• G1 – Tangential Continuity - This ensures that the edge at the end of the untwisted section is tangent to the edge at the beginning of the twist. 

• G2 – Curvature Continuity - This ensures that the curvature at the end of the untwisted section is the same as the curvature at the beginning of the twist. This option is one level of continuity higher than tangent continuity. Curvature continuity uses a 5th degree polynomial as compared to the 3rd degree (cubic) used for tangential continuity. This more naturally approximates what a real part would do when it deforms.

Above > The part before twisting

Above > The part after a 275 degree twist. The twist region starts at the centerline of the first hole and ends at the tip