Creating a Spine

This task shows how to create a spine, that is a curve normal to a list of ordered planes or planar curves. These spines are useful when creating complex surfaces such as swept, lofted, or filleted surfaces.
 

Creating a Spine Based on Planes
Open the Spine1.CATPart document.

  1. Click Spine from the Curves toolbar.

    The Spine Curve Definition dialog box is displayed.

  2. Successively select planes or planar profiles. 

  3. Click Preview. 

    The spine is displayed.

  4. You can also select a start point.

    The point is projected onto the first plane as the spine starting point, as illustrated here (point.3 is selected) except if it is already lying onto this first plane.

    • Use the contextual menu on the Start point field to create a point. (See Stacking Commands). 

    • If you do not select a start point (default mode) one is computed automatically.

    • To remove a selected point, check the Computed start point option.

  5. Select one of the elements in the dialog box, then click: 

    • Replace, then select the replacing element in the geometry or the specification tree

    • Remove to delete it from the spine definition

    • Add then select a new element to be added after the last one.
    Using the contextual menu, you can choose to Add After or Add Before the selected element.

  6. Click OK.

    The curve (identified as Spine.xxx) is added to the specification tree.
    When non planar curves are selected, their mean planes are used to compute the spine.

Creating a Spine Based on Guiding Curves

Open the Spine2.CATPart document.

  1. Click Spine .

    The Spine Curve Definition dialog box is displayed.

  2. Click within the Guide list and successively select two guiding curves.

    The spine is immediately previewed.

  3. Click OK to create the spine. 

    The curve (identified as Spine.xxx) is added to the specification tree.
    This type of spine is very useful when creating a swept surface, as illustrated below:
    Swept surface without any spine Swept surface with specified spine

 

Reversing the Spine's Starting Direction
This option can only be used if the first profile is a plane.

Open the Spine3.CATPart document.
 

  1. Double-click the spine.

    The Spine Curve Definition dialog box is displayed.

  2. Click Reverse Direction.

  3. Click OK to create the reverse spine.