Class Hierarchy
AcRxObject AcGiDrawable AcDbObject AcDbAssocAction AcDbAssoc2dConstraintGroup
C++
class AcDbAssoc2dConstraintGroup : public AcDbAssocAction;
File
AcDbAssoc2dConstraintGroup.h
Description
The AcDbAssoc2dConstraintGroup class represents a set of geometric constraint relations between subentities of geometric entities. All the geometries must lie in a single plane.
The AcDbAssoc2dConstraintGroup object owns the constraints that are derived from the AcGeomConstraint class, and "proxies" of the constrained geometries, derived from the AcConstrainedGeometry class. AcConstrainedGeometries often refer to subentities of AutoCAD entities and the AcDbAssoc2dConstraintGroup owns AcDbAssocGeomDepedencies on these entities. It also owns AcDbAssocValueDependencies on the AcDbAssocVariables that are the values of dimensional constraints (represented by classes derived from AcExplicitConstraint).
If the dimensional constraint has a graphical representation, such as in the form of an AcDbDimension entity, the AcExplicitConstraint also owns AcdbAssocDependency owning an object derived from AcDbAssocDimDependencyBody that facilitates the interaction between the AcExplicitConstraint, the AcDbAssocVariable keeping the value of the dimensional constraint, and the AcDbDimension (or other object/entity) that serves as a graphical representation of the dimensional constraint.
The evaluate() method of this action takes the current properties of the referenced geometries and the current values of the variables referenced by AcExplicitConstraints. Then it invokes a constraint solver that finds new positions and shapes of the constrained geometries so that they satisfy the constraints. Finally the referenced geometries are updated to their new positions and shapes. The evaluate() method call may fail if a solution satisfying all the constraints can not be found..
Links
AcDbAssoc2dConstraintGroup Enumerations, AcDbAssoc2dConstraintGroup Methods