DG Kernel (ActiveX) Documentation


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IBooleanEntity_DG Interface

Subtract
Unite
Intersect
SurfaceIntersection

Interface for performing Boolean operations

See also: Bool Op sample


void Subtract(IEntity_DG entity)

Subtracts entity from this. entity remains inchanged. Use IEntity_DG.Clone() prior the operation if this entity has to remain unchanged also.

When both entites have "BRep" geometry type, geometry of this entity becomes a compound shape (Implements IBRepCompound_DG) because the result may not be a linked (single piece) geometry.

Individual shapes can be accessed via:
thisEntity > IEntity_DG.GetGeometry() > IGeometry_DG > GetGeometryType()
IGeometry_DG > IBRepGeometry_DG > GetShape() > IBRepShape_DG > GetShapeType()
IBRepShape_DG > IBRepCompound_DG > GetShapeCount()
IBRepCompound_DG > GetShape(index) > IBRepShape_DG > GetShapeType()

If either entity has other than "BRep" geometry type, they both are cloned to "Mesh" type and the result of the operation, which is also a geometry of "Mesh" type is stored in this entity as its new geometry. Query IMesh_DG from geometry of this: thisEntity > IEntity_DG.GetGeometry() > IGeometry_DG > IMesh_DG to access the mesh.


void Unite(IEntity_DG entity)

This entity changes to union of this and entity. entity remains inchanged. Use IEntity_DG.Clone() prior the operation if this entity has to remain unchanged also.

When both entites have "BRep" geometry type, geometry of this entity becomes a compound shape (Implements IBRepCompound_DG) because the result may not be a linked (single piece) geometry

Individual shapes can be accessed via:
thisEntity > IEntity_DG.GetGeometry() > IGeometry_DG > GetGeometryType()
IGeometry_DG > IBRepGeometry_DG > GetShape() > IBRepShape_DG > GetShapeType()
IBRepShape_DG > IBRepCompound_DG > GetShapeCount()
IBRepCompound_DG > GetShape(index) > IBRepShape_DG > GetShapeType()

If either entity has other than "BRep" geometry type, they both are cloned to "Mesh" type and the result of the operation, which is also a geometry of "Mesh" type is stored in this entity as its new geometry. Query IMesh_DG from geometry of this: thisEntity > IEntity_DG.GetGeometry() > IGeometry_DG > IMesh_DG to access the mesh.


void Intersect(IEntity_DG entity)

Intersects this with entity. entity remains inchanged. Use IEntity_DG.Clone() prior the operation if this entity has to remain unchanged also.

When both entites have "BRep" geometry type, geometry of this entity becomes a compound shape (Implements IBRepCompound_DG) because the result may not be a linked (single piece) geometry. Use IEntity_DG.Clone() prior the operation if this entity has to remain unchanged also.

Individual shapes can be accessed via:
thisEntity > IEntity_DG.GetGeometry() > IGeometry_DG > GetGeometryType()
IGeometry_DG > IBRepGeometry_DG > GetShape() > IBRepShape_DG > GetShapeType()
IBRepShape_DG > IBRepCompound_DG > GetShapeCount()
IBRepCompound_DG > GetShape(index) > IBRepShape_DG > GetShapeType()

If either entity has other than "BRep" geometry type, they both are cloned to "Mesh" type and the result of the operation, which is also a geometry of "Mesh" type is stored in this entity as its new geometry. Query IMesh_DG from geometry of this: thisEntity > IEntity_DG.GetGeometry() > IGeometry_DG > IMesh_DG to access the mesh.


IEntity_DG SurfaceIntersection(IEntity_DG entity)

Returns 1D intersection of surfaces. This and entity remain unchanged.

When both entites have "BRep" geometry type the returned entity also has "BRep" geometry. Its BRep shape is a compound (Implements IBRepCompound_DG), which consists of edges. It is recommended to verify that via:
ReturnedEntity > IEntity_DG.GetGeometry() > IGeometry_DG > GetGeometryType()
IGeometry_DG > IBRepGeometry_DG > GetShape() > IBRepShape_DG > GetShapeType()
IBRepShape_DG > IBRepCompound_DG > GetShapeCount()
IBRepCompound_DG > GetShape(index) > IBRepShape_DG > GetShapeType()
IBRepShape_DG > IBRepEdge_DG > GetCurve() > ....

If either entity has other than "BRep" geometry type, they both are cloned to "Mesh" type for the operation. The returned entity is a group (an empty entity), children of which have geometry of "SegmentStrip" type. A group is retuned as the resulting sampled line often consists of several isolated closed loops.

To access the set of loops: Call IEntity_DG.GetChildCount(). If the returned number is zero, the enties do not intersect. To get the k-th intesection loop use:
ReturnedEntity > GetChildAt(k) > IEntity_DG > GetGeometry() > IGeometry_DG > IPointSetGeometry_DG > GetPoints() > IPointArray_DG.