Creating a Tube Surface

This task explains how to create open or closed tube surfaces with a specified radius.
The moving frame defines a local coordinate system that is moved along a guide curve. Different variants can be realized by a combination of options on the 'Options' tab.
  Radius 20, Close, and Center

Creation of a tube surface around the spine curve.

 Radius 20, Blend, and Close

Creation of a tube surface touching the x or y axis of the local coordinate system.
  Radius 20, and Blend

Creation of a tube surface touching the x or y axis of the local coordinate system. The surface begins in the touching point on the x axis, and ends in the touching point on the y axis.

 Radius 20, Blend, and Distance 10 (Distance > 0)

Creation of a tube surface touching the x axis of the local coordinate system, and having a distance 10 from the y axis. The surface begins in the touching point on the x axis, and ends parallel to the y axis.
  Radius 20

Creation of a tube surface touching the x axis of the moving frame. The surface begins in the origin on the x axis, and ends parallel to the y axis.

 Radius 20, Blend, and End Angle 135° (Close)

Creation of a tube surface touching the x or y axis of the moving frame. The surface begins in the touching point on the x axis, and ends when it has an angle of 135° with the y axis.
  Radius 20, Blend, and Start Angle 135° (Close)

Creation of a tube surface touching the x or y axis of the moving frame. The surface begins in the touching point on the y axis, and ends when it has an angle of 135° with the x axis.

    
  Radius 20, and Reference

Creation of a tube surface lying on the reference surface. It begins in the projection of the spine curve in the direction of the y axis, is tangential to the reference, and ends parallel to the y axis.

 Radius 20, Blend, and Reference

Creation of a tube surface lying on the reference surface. It is tangential to the reference, and ends at the touching point on the y axis.
Open the Tubing.CATPart document.

  1. Click the Tubing icon .
    The 'Tubing' dialog box is displayed.

  1. Select the curve as Guide, enter a Radius of 20mm and click Apply. A tube surface touching the x axis of the moving frame will be displayed. The surface begins in the origin on the x axis, and ends parallel to the y axis.

  1. Activate the options Center and Close, and click again Apply. The tube surface will be created around the guide curve.

  1. Deactivate Center, activate Blend instead and click Apply. A tube surface touching the x or y axis of the local coordinate system will be created.

  1. Deactivate Close and click Apply. Now also a tube surface touching the x or y axis of the local coordinate system. This surface begins in the touching point on the x axis, and ends in the touching point on the y axis.

  1. Enter a Distance of 10mm and click Apply. A tube surface touching the x axis of the local coordinate system and having a distance 10 from the y axis will be created. The surface begins in the touching point on the x axis, and ends parallel to the y axis.

 
You can define the following options:
  • Guide: Selection of the guide curve for the moving frame.
  • Reference: Selection of a reference surface where the tube surface shall be positioned.
  'Options' tab
 
  • Create Tubing
     
    • Center: The center point of the tube surface is moved as follows relating to the origin of the local coordinate system:
      • OFF: The center point is moved along the y axis in a way that the surface touches the x axis.
      • ON: The center point is lying on the x axis.
    • Radius: Radius of the tube surface.
    • Blend: The center point of the tube surface is moved as follows relating to the origin of the local coordinate system:
      • OFF: The center point is lying on the y axis.
      • ON: The center point is moved along the x axis.
        • Distance = 0: The center point is moved in a way that the surface touches the y axis.
        • Distance > 0: The center point is moved in a way that the surface has the specified distance from the y axis.
 

Positioning the centre point with the options Centre, Blend, and Distance
 
  • Close: An open or closed tube surface can be created.
    • OFF: Creation of an open tube surface. As start and end angle, the angles between the cross tangents of the start and end edges of the tube surface and the X axis of the local coordinate system are measured.
      If a reference surface is selected, the angle is measured relative to the tangent plane of the reference surface.
      • Start/End Angle: Only available if 'Close' is inactive.
        Defines the angle of the open tube surface.
    • ON: Creation of a closed tube surface.
  Open tube surface with different start and end angles
 
  • Create Curve: Curves will be created in addition to the surface by activating these check buttons. These curves have the shape of the guide curves and run:
    • along the edge at the surface's Start
    • along the edge at the surface's End
    • through the surface's Center point
    • through the theoretical Corner

Creation of additional curves

 
  See  'Moving Frame' tab
  See  'Approximation' tab
  See 'Output' tab
  Click onto the 'More Info' button to display deviations and output results.
 
  • Display: Depending on the options selected, values are displayed in the graphics area.
  • Deviation
    • Circle: Deviation of the approximated Bezier surface from an exact circle. Can be influenced through the segmentation.
    • Reference: Deviation between the newly created tube and the reference geometry.
  • UV: Display of the UV vectors of curves and surfaces.
  • MFT: Display of the local coordinate system for the moving frame type.
  • Output Result: See Output Result