geom/doc/salome/gui/GEOM/input/partition.doc

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\page partition_page Partition

For a detailed description of the Partition operation please refer to <a href="SALOME_BOA_PA.pdf">this document</a>.
It provides a general review of the Partition and Boolean operations algorithms, describes the usage methodology and highlights
major limitations of these operations.

Perhaps you also ask yourself : \ref partition_explanation "What's the difference between partition, compounds and fuse operation ?"

To produce a \b Partition in the <b>Main Menu</b> select <b>Operations - > Partition</b>

This operation builds a compound by intersection of several shapes
with a set of tool objects or with a plane.
The \b Result will be a \b GEOM_Object.

<br><h2>Intersection of two shapes.</h2>

\image html partition1.png

<b>Arguments:</b> Name + 2 lists of shapes (the shapes from the
first list will be intersected with the shapes from the second list) +
Resulting Type of shape.

As far as the intersection of two objects can produce any type of
geometrical objects, <b>Resulting type</b> box allows choosing the
preferable result, i.e. a solid, a shell, a list of faces, etc.

The <b>Resulting type</b> has to be equal or lower than the type of the
\em Objects. In other words, if the \em Objects don't contain any
shape of this type, Partition fails.

<b>Keep shapes of lower type</b> checkbox manages standalone shapes of
type other than the \em Limit. If it is checked, lower dimension
objects will be preserved, else they will be lost.

For example, you partition a box (Solid) and a face (Face)
without any tool (the box is split in two parts by the shape). If you
choose the Resulting Type "Solid", you will
obtain a compound of two solids, but if you also check <b>Keep shapes of lower
type</b> checkbox, you will obtain a compound of two solids and one
face (there will be a hole in the resulting face, where the original
face intersects with the box, see the corresponding \ref partition_picture_3 "picture" below).

<b>No sub-shapes intersection (Compounds only)</b> check box affects
only input shapes of the Compound type.
- If this option is switched off (default behavior) each input compound will be automatically
exploded into sub-shapes and the intersection between these shapes will be also computed.
- If this option is switched on, the intersection between sub-shapes will not be performed.
In this case the Partition algorithm will work faster, but the result might differ from the 
default behavior.

<b>Detect Self-intersections</b> check box is used to check self-intersection of arguments.
- If this option is switched on (by default), each input shape is checked for self-intersection.
If self-intersection is detected, the operation is aborted.
- If this option is switched off, the partition algorithm is performed without self-intersection
checks.

\note This algorithm does not find all types of self-intersections. It is tuned
      to detect vertex/vertex, vertex/edge, edge/edge, vertex/face and edge/face
      intersections. Face/face intersections detection is switched off as it
      is a time-consuming operation that gives an impact on performance. To find
      all self-intersections please use \ref check_self_intersections_page
      "Detect Self-intersection tool".

- Activate \ref restore_presentation_parameters_page "Advanced options" if required.

\note Partition is a complex operation, so its result of it depends
      on the quality of the initial shapes. Sometimes, if partition fails,
      such healing operations as <b>Shape Processing</b>
      and <b>Limit Tolerance</b> can help to attune source shapes to obtain correct result of the Partition.
      See also \ref tui_limit_tolerance "TUI example" of shape healing.

<b>TUI Command (with sub-shapes intersection):</b>

<em>geompy.MakePartition(ListOfShapes, ListOfTools, ListOfKeepInside,
ListOfRemoveInside, Limit, RemoveWebs, ListOfMaterials,
KeepNonlimitShapes, checkSelfInte)</em>

<b>TUI Command (without sub-shapes intersection):</b>

<em>geompy.MakePartitionNonSelfIntersectedShape(ListOfShapes,
ListOfTools, ListOfKeepInside, ListOfRemoveInside, Limit, RemoveWebs,
ListOfMaterials, KeepNonlimitShapes, checkSelfInte)</em>

Here,
- \em ListOfShapes is a list of shapes to be intersected
- \em ListOfTools is a list of shapes to intersect the shapes from
\em ListOfShapes
- \em Limit is a Type of resulting shapes
- \em KeepNonlimitShapes is a flag that allows to preserve standalone
shapes of low dimension (than \em Limit) in the result.
- \em checkSelfInte is a flag that indicates if the arguments should
be checked for self-intersection prior to the operation.
- Other parameters are obsolete and kept only for compatibility with
previous versions of SALOME.

<br><h2>Intersection of a Shape and a Plane.</h2>

\image html partition2.png

<b>Arguments:</b> Name + 1 shape to be intersected + 1 cutting plane.

Activate \ref restore_presentation_parameters_page "Advanced options" if required.

<b>TUI Command:</b>

<em>geompy.MakeHalfPartition(Shape, Plane, checkSelfInte)</em>, where:
- \em Shape is a source shape to be intersected by the \em Plane
- \em Plane is a tool shape, to intersect the \em Shape.
- \em checkSelfInte is a flag that indicates if the arguments should
be checked for self-intersection prior to the operation.

<b>Examples:</b>

\image html partitionsn1.png "Box intersected by a plane"

\image html partitionsn2.png "Result of intersection"

\anchor partition_picture_3
\image html partitionsn3.png "Result of intersection of a box and a plane (both as \em Objects, no tools) with the Resulting type \em Solid and checked 'Keep shapes of lower type'"

Our <b>TUI Scripts</b> provide you with useful examples of \ref tui_partition "Basic Operations".

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