Deforming Surfaces According to
Shape Morphing

This command is only available with the Generative Shape Optimizer product.
This task shows how to deform surfaces basing the deformation on shape morphing, that is matching each reference curve or point (reference elements) onto a target curve or point (target elements)
The deformation is then defined by the transformation of the reference curves or points into target curves or points.
The elements used for the deformation do not necessarily lie on the initial surface.
Several cases are presented here, from the simplest one to cases using various options. Note that whatever information is given in the first example also applies to the following examples.

Open the ShapeMorphing1.CATPart document.
 

Basic shape morphing deformation

  1. Click ShapeMorphing .

    The Shape Morphing Deformation Definition dialog box is displayed.

  2. Select the surface to be deformed.

  3. Successively select the first reference element and the first target element.

  4. Repeat this operation by selecting the second reference element then the second target element.

    As you select pairs of reference/target elements, the list in the Deformation Elements tab is updated accordingly.

  5. Click Preview to visualize the deformation.

    The previsualization shows that:
    • the deformation is applied to a group of points
    • there is a constraints' mapping between the reference and the target curves.
    You can visualize the mapping constraint by selecting a number in the Constraint dialog box.

  6. Click OK to create the deformed surface.

    The element (identified as Shape Morphing.xxx) is added to the specification tree.
    You can apply a constraint on the target element with the associated support surface.
    The combo list displays the available continuity types depending on the reference/target elements you chose.

    • If you select a reference and a target element, the Point and the Tangent continuity are available.
      In the case of Point continuity, the Support field is grayed.

      In the case of Tangent continuity, select a support surface so that the continuity is kept.

    • If you select only reference elements, all continuities (Point, Tangent, and Curvature) are available.
      In the case of Tangent or Curvature continuity, you do not need to select a support surface as the surface to deform is taken into account.

Defining a Limit Element
  You can define a limit curve to determine the area of the deformation and enable the other part of the surface to remain frozen.
Here is an example using Limit1. as Limit curve and a Tangent Continuity.
The Reverse Direction button enables to deform the surface on the other side of the limit curve. You can also click the arrow in the 3D geometry.
 

 

Coupling Points
  Use this tab to define coupling points in order to map reference elements with target elements.
 
Points must be located on reference and target curves.
 
 

  • You must always select successively a reference then a target element to define a pair. You cannot select all reference elements, then all target elements for example.

  • When several pairs of curves are selected, they must be ordered, not randomly selected
   
Reference and target curves can be multi-cells. Joined, blended, or matched curves, for example, can be used as reference or target curves.

Shape Morphing Deformation with a Fixed Element
Sometimes, you need to create a deformed surface in relation to another element. The shape morphing capability lets you fix an element that can be used by another one, thus allowing you to retain a connection between elements while deforming the initial surface.

  1. Click ShapeMorphing .

    The Shape Morphing Deformation Definition dialog box is displayed.

  1. Select the surface to be deformed.

  2. Select the first reference element.

  3. Select the target element.

  4. Click Add to add another reference element.

  5. Successively select the second reference element then the target element.

  6. Click OK to create the deformed surface.
 

Diagnosis
  This capability lets you visualize the deviations in the 3D geometry when the result is not fully accurate.
The Warnings dialog box may also be displayed. Refer to the Managing Warnings chapter for further information.
Open the ShapeMorphing2.CATPart document.

  1. Click ShapeMorphing .

    The Shape Morphing Deformation Definition dialog box is displayed.

  1. Select the surface to be deformed (Surface.1).

  2. Select the reference and target elements as shown in the picture below:

  3. Click Preview to visualize the deviations:

    The Warnings dialog is also displayed. Refer to Managing Warnings for further information.

  4. Select a line in the dialog box to display the corresponding mapping and deviation.

    Here are the cases where warnings are displayed.
    • When inputs are of bad quality:

      • If the reference or target curves are not continuous.

      • If the reference or target curves are not continuous in tangency or in curvature and the discontinuities are not coupled.

    To solve the above warnings, we advise you to :

    1. use the Curve Smooth command to smooth the small discontinuities, then

    2. use the coupling point tab to associate the great tangency or curvature discontinuities between target and reference.
    • When reference curves intersect, there may be an incompatibility between constraints:
      • If the targets do not intersect
      • If the targets intersect but the mapping between reference and targets do not associate the reference's intersection with the targets' intersection. In this case, we advise you to add coupling points.
      • If the tangency constraint cannot be guaranteed.