Creating Offset Surfaces

You can create a surface by offsetting an existing surface.

1. Click Offset in the Offsets sub-toolbar.

   The Offset Surface Definition dialog box appears.
   
   

2. In the Surface box, select the surface to be offset.

   An arrow indicates the proposed direction for the offset.

3. In the Offset box, type the value or use the arrows to change the value.

   
   
   

4. Click Preview to preview the offset surface.

   The offset surface is displayed normal to the reference surface.
   
   

5. Click OK to create the surface.

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

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.

You can remove the sub-elements using the Sub-Elements to remove tab. The Sub-Elements to remove tab helps you for the analysis in case the offset encounters a problem.

1. Perform steps 1 to 3 above.

2. Click Preview.

   The Warning dialog box appears and informs you that some sub-elements are erroneous. The geometry shows these sub-elements and flag notes display sub-elements to remove.

   There are different colored flag notes to display the severity of errors:

   The red-colored flag shows that the error is critical.

   The yellow-colored flag depicts warning.

   The white-colored flag 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.

   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.

   Warning: 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 specification tree.

4. Click Preview.

   The offset surface is displayed normal to the reference surface.

5. Click OK to create the surfaces.

   The surfaces (identified as Offset.xxx) are added to the specification tree.
   
   

You can apply smoothing on the offset surface.

1. In the Smoothing list, select the smoothing type on the offset surface:

   
   

   • 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. A warning message is launched and the modified surface is shown in the 3D geometry. If a surface still cannot be offset, no smoothing is performed and a warning 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 a warning 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. Select the Regularization type on the offset surface:

   
   

   • Local: regularizes the offset surface locally to minimize the deviation.
   • Global: regularizes the offset surface completely. If the local regularization fails, by default, the offset surface is globally regularized.

Important: 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.