Trimming Volumes

This task shows how to trim a volume to define the elements to be kept or removed while performing the union operation.
Open the TrimVolume1.CATPart document and make sure Geometrical Set.1 is the current body.
  This is your initial data: the Trim part is composed of two shells contained in one geometrical set.
 

  1. Click Union Trim from the Volumes operations sub-toolbar.

    The Trim Definition dialog box opens.

  2. Select the Volume to trim, i.e. Shell.2.

  3. Select the Cutting Volume, i.e. Shell.1.

  4. Click the Faces to remove field and select Shell.2 's inner face.

    The selected face appears in pink, meaning that the application is going to remove it.

  5. Click the Faces to keep field and select Shell.1 's inner face.

    The selected face appears in light blue, meaning that the application is going to keep it.
    Faces to remove and Faces to keep must belong to the same volumes as the selected Volume to trim and Cutting volume.

  6. Click Preview to you check whether your specifications meet your needs or not.

  7. Click OK to compute the material to be removed.

    The operation (identified as Trim.xxx) is added to the specification tree.
    The specification tree and the Trim part now look like this:
    The multi-output capability is available. Click to display the list of selected faces.
       
    • You can edit a Trim feature and modify the cutting volume. To do so, simply double-click the feature in the specification tree and then select a new volume in the Cutting volume field.
    • You can also swap the input volumes: right-click the Volume to trim field and select the Swap operands contextual item.
      This capability only works when both volumes belong to the same geometrical set or ordered geometrical set.
    • Adding a body to a solid body and vice versa is possible. In that case, the second body you select remains at the same location in the specification tree once the Boolean operation is done. To see an example, refer to Mixed Boolean Operations.
       
    • Avoid using input elements that are tangent to each other since this may result in geometric instabilities in the tangency zone.
    • As much as possible, avoid selecting volumes trimmed by the operation. In some cases, defined trimmed volumes have the same logical name: the application then issues a warning message requiring a better selection.
    • If you want to perform the Union Trim operation and create a datum feature, you need to activate the Create Datum command. Ensure that you activate it only after selecting the required volumes and faces in the Trim Definition dialog box and before clicking Preview. Activating the datum command at any other instance may result in the failure of the Trim operation.