Creating Offset Surfaces

You can create an offset of a surface or a set of surfaces. It can be any type of surface, including multi-patch surfaces resulting from fill or any other operation.

This task shows you how to:

Before you begin: Create a 3D shape containing a surface.
See Also
About the Offset Command

Create an Offset Surface

  1. From the Idealize section of the action bar, click Offset .
  2. In the Surface box, select a surface or a set of surfaces.
    An arrow indicates the proposed offset direction.
  3. Specify the offset distance by entering the value in the Offset box or manipulating the arrows in the work area.
  4. Click Preview to preview the offset surface.
    The offset surface is displayed normal to the reference surface.

  5. Click OK.

Important:
  • Depending on the geometry configuration and the offset value, an offset may not be allowed as it would result in a debased geometry. In this case, you need to decrease the offset value or modify the initial geometry.
  • When you modify an input value through the dialog box, such as the offset value or the direction, the result is computed only when you click Preview or OK.

Remove Sub-Elements

You can remove sub-elements in case of problems for offset creation.

  1. Perform steps 1 to 3 above.
  2. Click Preview.
    An informative prompt appears informing that some sub-elements are erroneous. The geometry shows these sub-elements and flag notes display sub-elements to remove.

    Different colored flag notes display the severity of errors:

    Shows that the error is critical.
    Depicts warning.
    Shows information regarding the offset.


  3. Click Yes to accept the offset.
    In the dialog box, the Sub-Elements to remove tab lists the erroneous sub-elements and a preview of the offset is displayed.
    Important:
    • This list is stable at update but not always when you create a new offset. As a consequence, the erroneous sub-elements in the list may be different.
    • The list is not available if Automatically Computes Sub-elements To Remove is selected.
    Tips:
    • If you move the pointer 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.
    As this list is not always optimal, you can manually add or remove sub-elements:
    • 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.
    Important:
    • If you double-click Add Mode or Remove Mode, 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. If you modify an input in the Offset Surface Definition dialog box, the list is re-initialized. However, it is not re-initialized if the input is modified through the offset parameter in the tree.
    Note: The availability of context commands depend on the location where you activate the context menu, and the context commands act only on the lines that you right-click. If more than one lines are highlighted, right-clicking one highlighted line is equivalent to right-clicking all the highlighted lines at the same time. In this case, the context command acts on all the highlighted lines. Consider the following cases:
    • Case 1: line 1 is highlighted and line 1 is right-clicked: the selected command from the context menu will act on line 1.
    • Case 2: line 1 is highlighted and line 2 is right-clicked (but not highlighted): the selected command from the context menu will act on line 2.
    • Case 3: line 1 and line 2 are highlighted and line 1 is right-clicked: the selected command from the context menu will act on both line 1 and line 2.
    • Case 4: line 1 and line 2 are highlighted and line 3 is right-clicked (but not highlighted): the selected command from the context menu will act on line 3.
  4. Click Preview.
    The offset surface is displayed normal to the reference surface.
  5. Click OK.


  6. Select Automatically Computes Sub-Elements To Remove check box.

Remove Sub-Elements Automatically

You can automatically remove sub-elements to obtain a better result after a modification of the offset value in the tree.

Before you begin: Create a 3D shape containing a surface.
  1. Create an offset surface as described in steps 1 to 2 in Creating Offset Surfaces.
  2. Select Automatically Computes Sub-Elements To Remove.
  3. Click Yes in the Warning box.
    The sub-elements to remove and flag notes are displayed on the geometry. The Sub-Elements to remove list in the Offset Surface Definition dialog box is empty and you cannot add or remove sub-elements.
  4. Click OK.


  5. In the tree, double-click the Offset parameter of the Offset.x feature and change the offset value in the Edit Parameter dialog box.


    The offset result is correctly computed with the modified value. In the example, a sub-element is added to the offset result.

Smooth an Offset Surface

You can apply smoothing on the offset surface.

  1. In the Smoothing list, select the smoothing type on the offset surface.
    OptionDescription
    None The smoothing is constant. This is the default type.
    Automatic A local smoothing is applied only if the constant offset cannot be performed. It cleans the geometry of the surface and enables the offset. An informative message is displayed and the modified surface is shown in the 3D geometry. If a surface still cannot be offset, no smoothing is performed and an informative message is issued (as in the constant offset mode). If you click Yes, erroneous sub-elements are removed and the offset operation goes on.
    Manual A local smoothing is applied as in the Automatic type. You need to define a Maximum Deviation below which the elements are to be offset. If the resulting deviation is greater than the defined deviation, no smoothing is performed and an informative message is issued (as in the constant offset mode). If you click Yes, erroneous sub-elements are removed and the offset operation goes on.
  2. In the Regularization list, select the regularization type on the offset surface.
    OptionDescription
    Local Regularizes the offset surface by adding local modifications to the offset surface. Therefore, using this option, the deviation between the offset surface and the surface to be offset is minimized. This option improves the robustness of the offset computation.
    Global Regularizes the offset surface completely. The same deviation is applied everywhere. If the local regularization fails, by default, the offset surface is globally regularized.

Important:
  • Smoothing, Regularization and Maximum Deviation parameters are only available with the Generative Shape Morphing app or Hull Form Modeling app.
  • The Regularization option is available only with Automatic and Manual smoothing type.
  • The deviation should be comprised between 0.001mm and the Offset value (-0.1mm). For instance, if the Offset value is 20mm, the maximum deviation is 19.9mm.
  • The Maximum Deviation box is only available with the Manual smoothing type.