• Keeping or Removing Elements
• Intersecting and extrapolating
• Splitting Wires
• Splitting a surface by a curve or a surface by a surface
• Splitting closed surfaces by two connex surfaces or curves
• Splitting A Surface When The Intersection Is Not Connex
• Splitting Volumes

Open the Split1.CATPart document.

1. Click Split .

   The Split Definition dialog box appears.

2. Select the element to be split.

   You should make your selection by clicking on the portion that you want to keep after the split.
   	You can select several elements to cut. In that case, click Element to cut again or click . The Elements to cut dialog box opens. Select as many elements as needed. Click Close to return to the Split Definition dialog box. The number of selected elements is displayed in the Element to cut field.
   	Click Remove or Replace to modify the elements list. When several elements to cut are selected, the selected portions are not taken into account as parts to keep. The parts to be kept depend on the type of the cutting element (point, curve, surface, etc.) and the orientation of cutting elements and the elements to cut. Click Other side to reverse the portion to be kept, element by element.

3. Select the cutting element.

   A preview of the split appears. You can change the portion to be kept by selecting that portion.
   You can also select the portion to be kept by clicking the Other side button. This option applies on all selected elements to cut.
   	You can select several cutting elements. In that case, note that the selection order is important as the area to be split is defined according to the side to be kept in relation to the current splitting element.
   	You can create a Join as the splitting element, by right-clicking Cutting elements and choosing Create Join. If you split a surface and you keep both sides by joining the resulting splits, you cannot access the internal sub-elements of the join: indeed, splits result from the same surface and the cutting elements are common.

4. Click OK to split the element.

   The created element (identified as Split.xxx) is added to the specification tree.
   In the case several elements to cut were used, the created elements are aggregated under a Multi-Output.xxx feature.
   In the illustrations below, the top-left line is the first splitting element. In the left illustration it defines an area that intersects with the other three splitting curves, and in the illustration to the right, these three elements are useless to split the area defined by the first splitting element.
   Would you need to remove or replace one of these cutting elements, select it from the list and click Remove or Replace .

Keeping or Removing Elements

1. Click Show parameters >>.
2. Click in the field of your choice to be able to select the elements in the 3D geometry.
3. Right-click in the field either to clear the selection or display the list of selected elements.

   Only the selected element is removed. All other elements are kept
   The selected elements are kept. All other elements are removed
   You must select sub-elements as elements to keep or to remove; otherwise, a warning message is issued. You can also select a point to define the portion to keep or to remove. A contextual menu is available on the Elements to remove and Elements to keep fields. You do not need to select elements to keep if you already selected elements to remove and vice-versa. Select Keep both sides to retain the other side of the split element after the operation. In that case it appears as aggregated under the first element. Therefore both split elements can only be edited together and the aggregated element alone cannot be deleted. If you use the Datum mode, the second split element is not aggregated under the first one, but two datum surfaces are created. Avoid splitting geometry when the intersection between the element to cut and the cutting element is merged with an edge of the element to cut. We advise you to use the Elements to remove and Elements to keep options to remove the positioning ambiguity. In case there are several elements to cut, Keep/Remove and Keep both sides only apply on the first selected element. In case the intersection between the elements is not connex, an error message may be issued prompting you to choose the elements to be kept or not. Select the Ignore no intersecting elements check box to split many elements (curves, surfaces, volumes) when the cutting element does not intersect all the elements. When this option is selected, the Intersections computation option is cleared and grayed out. Select the Keep elements in half space check box to keep all the elements that are on one side of the cutting infinite plane. The cutting element defines this half space. This option applies only when the cutting element is an infinite plane. If the split side is not towards the element to cut, an error message is issued. Note that this behavior differs from the behavior in the Part Design workbench, i.e. no error message is issued. When this option is selected, the Ignore no intersecting elements option is automatically selected and grayed out.
   Elements to cut: dark blue and light blue surfaces Cutting elements: yellow and purple planes
   Result with Ignore no intersecting elements selected
   Element to cut: non connex light blue surface Cutting element: yellow plane
   Result with Keep elements in half space selected

Intersecting and extrapolating

• Select Intersections computation to create an aggregated intersection when performing the splitting operation. This element will be added to the specification tree as Intersect.xxx.

  	In case there are several elements to cut, the Intersections computation option only applies on the first selected element.

• Clear Automatic extrapolation if do not you want the automatic extrapolation of the cutting curve.

  When a splitting curve is extrapolated, the extrapolation will be performed on the original curve, providing the underlying geometry (that is the curve) is long enough to be used for the extrapolation.

  If Automatic extrapolation is deselected, an error message is issued when the cutting element needs to be extrapolated, and the latter is highlighted in red in the 3D geometry.

  	This option is available in the case of a split surface/curve or surface/surface.

Splitting Wires

• When splitting a wire (curve, line, sketch and so forth) by another wire, you can select a support to define the area that will be kept after splitting the element. It is defined by the vectorial product of the normal to the support and the tangent to the splitting element. 

  This is especially recommended when splitting a closed wire.
  The non disconnected elements of the element to cut are kept in the result of the split.
  Splitting with no support selected, first solution	Splitting with no support selected, second solution
  Splitting with a selected support (xy plane), first solution	Splitting with a selected support (xy plane), second solution

  
Splitting a surface by a curve or a surface by a surface

The following steps explain how split a surface by a curve or another surface.

Split surface/curve

1. First, the cutting element (the curve) is laid down the surface.
2. Then, the result of step 1 is tangentially extrapolated in order to split the surface correctly (as shown in following figure). However, when this extrapolation leads to the intersection of the cutting element with itself prior to fully splitting the initial element, an error message is issued as there is an ambiguity about the area to be split.  

   	If the cutting element does not reach the free edges of the element to cut, an extrapolation in tangency is performed using the part of the cutting element that lays down the surface.

Split surface/surface

1. First, an intersection (the green wire) is created between the two surface elements.
2. Then, the result of the intersection is automatically extrapolated in tangency up to the closest free edges of the element to cut.

   The result of the extrapolation is used as the cutting element and the split is created.
   	Note that it is not the cutting element which is extrapolated but the result of the intersection.
   	If the result of the split is not what was expected, it is also possible to manually extrapolate the cutting element with the extrapolate feature before creating the split.

3. Extrapolate the cutting element (the red surface) in order to fully intersect the element to cut.
4. Then, use the extrapolated surface as the cutting element to split the surface.

   	Avoid using input elements which are tangent to each other since this may result in geometric instabilities in the tangency zone.

Splitting Closed Surfaces by Two Connex Surfaces or Curves

1. Click Join .

   The Join Definition dialog box appears.

2. Select Split.1 and Inverse.1 as the surfaces to be joined.

   Be careful that both surfaces or curves to join have coherent orientations. If it is not the case, use the Invert Orientation command to invert the orientation of one of the two surfaces or curves. Note that coherent orientations mean same orientations as the faces or edges of an equivalent connex splitting surface or curve:

3. Clear Check connexity .

4. Click OK to create the joined surface.
5. Click Split .

   The Split Definition dialog box is displayed.

6. Select Surface.1 as the Element to cut and Join.1 as the Cutting element.

7. Click OK to split the closed surface.

   	If the orientation of the elements composing the joined surface or curve is incoherent, an error message is issued when creating the split surface.

Splitting A Surface When The Intersection Is Not Connex

In this case, use the Elements to remove and Elements to keep options.

Splitting Volumes

• Replacing an input element does not change the result type,
• The switch between surface and volume is grayed out when editing the feature.
  If the result of the split is a volume, the split is a modification feature. If the result of the split is a surface, the split is a creation feature.
  To have further information about volumes, please refer to the Creating Volumes chapter.

The following capabilities are available: Stacking Commands and Selecting Using Multi-Output.