Entity Classes

Each HyperMesh entity type is represented by a corresponding class in the hm.entities Module. Consequently, every HyperMesh entity can be represented as a Python object. This object-oriented approach provides users with more power and flexibility. While in Tcl, entities are referred to mostly by their internal IDs, Python API works with entity objects.

The only exception is the include files (includes). Although they are treated as an entity type, include files are not a true entity, hence they do not have a dedicated Python class. This means that wherever an include or include entity type needs to be referenced, user is asked to supply the include ID (rather than a Python object) or refer to the entity type by the name string “includes” (rather that a Python class).

The entity class constructor has a dual functionality - it can be used to create a Python object representing an existing entity or it can be used to create a new entity and its Python object at the same time (see example below).

import hm
import hm.entities as ent

# Creating a Python object for property ID 10

model = hm.Model()
prop_10 = ent.Property(model,10)

# Creating a new property and its Python object

new_prop = ent.Property(model)

Via their attributes, entity objects provide users easy access to various entity characteristics. These attributes represent what we call in Tcl the entity Data Names. While many attributes might be available for a specific entity type across all its possible variations, each entity carries only attributes relevant to its configuration defined by the cardimage or config attribute.

Certain entity types use several configurations that differ significantly from each other and cannot be converted from one to another. In other words, for those entity types the entity configuration must be defined at the time of entity creation and it cannot be altered throughout the lifetime of the entity. In Python API, this setup is captured by providing a separate class for each configuration, each derived from a common base class that represents the core HyperMesh entity type. The table below shows which entity types follow this setup.

Entity Type	Configuration	Python Entity Class
Designpoints	1	DesignpointUndefined
	80	DesignpointImpactPoint
	81	DesignpointTargetPoint
Designpointmethods	1	DesignpointmethodUndefined
	2	DesignpointmethodESAComp
Designpointsets	1	DesignpointsetGeneric
	2	DesignpointsetBeam
	5	DesignpointsetRivets
	7	DesignpointsetSprings
	10	DesignpointsetBeamMember
	11	DesignpointsetBeamShellMember
	12	DesignpointsetBeamShell
	13	DesignpointsetBeamJoint
	14	DesignpointsetBeamShellSingle
	30	DesignpointsetPanelMetallic
	31	DesignpointsetPanelComposite
	32	DesignpointsetPanelStiffened
	34	DesignpointsetComposite
	40	DesignpointsetWeld
	80	DesignpointsetPedestrian
	81	DesignpointsetFMVSS
	82	DesignpointsetDummy
	83	DesignpointsetInstrumentPanelImpactPoint
Loads	9	LoadAcceleration
	3	LoadConstraint
	6	LoadFlux
	1	LoadForce
	2	LoadMoment
	4	LoadPressure
	5	LoadTemperature
	8	LoadVelocity
Plotcontrols	2	PlotcontrolContour
	5	PlotcontrolDeformed
	7	PlotcontrolFBD
	6	PlotcontrolMarker
	4	PlotcontrolTensor
	3	PlotcontrolVector
Structuralproperty	1	StructuralpropertyUndefined
	80	StructuralpropertyHeadForm
	81	StructuralpropertyUpperLegForm
	82	StructuralpropertyLowerLegForm
	83	StructuralpropertyDummyTargets
	84	StructuralpropertyInstrumentPanelIP
	85	StructuralpropertyEjectionMitigationIP
	100	StructuralpropertyBeam
	116	StructuralpropertyComposite
	117	StructuralpropertyWeld
	118	StructuralpropertyRivet
	300	StructuralpropertySpring
	400	StructuralpropertyPanelComposite
	401	StructuralpropertyPanelMetallic
	500	StructuralpropertyGeneric