Creating Variable Offset Surfaces

This command is only available with the Generative Shape Optimizer product.
This task shows you how to manage several variable and constant offset surfaces in one operation.
It also deals with the following subjects:
 
Open the VariableOffset1.CATPart document.

  1. Click Variable Offset .

    The Variable Offset Definition dialog box appears.

  2. Select the Base Surface to be offset (here Join.1).

  3. Select each sub-part to be offset (whether wires or surfaces) and define its offset type from the Offset drop-down list:

    • Variable: Applies a variable offset to the sub-part. The offset value field is grayed out.

    • Constant: Applies a constant offset to the sub-part. Specify the offset value.
    If the sub-part to offset is an element such as a line, curve, or edge, you can select the offset to be:
    • Constant (Border): The element is considered as a border element. Hence, it must lie on a boundary.
    • Constant (Inner): The element is considered as a constant constraint within a variable area. Hence it must lie in a variable area and not on a boundary.
    Both offset types apply to wires and surfaces.
    In our example, we defined a constant offset value of 40mm for Surface.1, a variable offset value for Surface.2 and a constant offset value of 20mm for Surface.3.
    You can use the following:

    • Add Before radio button: to add a surface before the selected surface,

    • Add After radio button: to add a surface after the selected surface,

    • Replace radio button: to replace the selected surface by another surface,

    • Remove button: to remove the selected surface.

  4. Click Preview.

    The offset surface is displayed normal to the reference surface.
    You can click Reverse Direction to reverse the offset direction.

  5. Click OK.

    One single feature is created: an automatic join of the resulting areas is performed if the result quality allows it (G1 connections).
    The surface (identified as Variable Offset.xxx) is added to the specification tree.
 

Removing Sub-Elements

The Sub-Elements to remove tab helps you for the analysis in case the offset encounters a problem.

Open the VariableOffset2.CATPart document.

  1. Click Variable Offset .

    The Variable Offset Definition dialog box appears.

  2. Select the Base Surface to be offset (here Global Surface).

  3. Select each sub-element to be offset (whether wires or surfaces) and define its offset type:

  4. Click Preview.

    The Warning dialog box appears, the geometry shows the erroneous sub-elements, and flag notes display sub-elements to remove.

  5. Click Yes to accept the offset.

    In the Variable Offset Surface Definition dialog box, the Sub-Elements to remove tab lists the erroneous sub-elements and a preview of the offset is displayed.
       
    • If you move the mouse over a flag note, a longer message giving an accurate diagnosis is displayed.
    • You can remove a sub-element by right-clicking it and choosing Clear Selection from the contextual menu.
    The following modes are optional, you may use them if you need to add or remove a sub-element to create the variable offset.
    • Add Mode: 
      when you click an unlisted element in the geometry, it is added to the list 
      when you click a listed element, it remains in the list
    • Remove Mode: 
      when you click an unlisted element in the geometry, the list is unchanged 
      when you click a listed element, it is removed from the list
    If you double-click the Add Mode or Remove Mode button, the chosen mode is permanent, i.e. successively selecting elements will add/remove them. However, if you click only once, only the next selected element is added or removed. You only have to click the button again, or click another one, to deactivate the mode.
       
    The list of sub-elements to remove is updated each time an element is added.
    Note that if you modify an input in the Offset dialog box, the list is re-initialized.

  6. Click Preview.

    The offset surface is displayed normal to the reference surface.

  7. Click OK to create the surface.

    The surface (identified as Variable Offset.xxx) is added to the specification tree.
 

Creating constant offset surfaces
  You can now create an offset surface whose sub-elements have several constant values. The offset surfaces are automatically extrapolated or split so that they connect together.
Open the VariableOffset3.CATPart document.

  1. Click Variable Offset .

    The Variable Offset Definition dialog box appears.

  2. Select the Base Surface as the Base Surface.

  3. Select each sub-element to be offset and apply a different constant offset value to each of them as shown in the picture below:

  4. Click OK to create the surface.

    • All adjacent surfaces that are tangent continuous must have the same offset value. Otherwise an error message is issued.
    • There should not be any fading edges between two surfaces that have different offset values.