Loads

Loads

The following sections identify load settings and discuss load limitation guidelines.

Load Settings

All functionality on the Setting dialog box Load Cases and Load Combinations tabs can be accessed by the API.

The following properties are available from the corresponding LoadCase BuiltInParameter:

Table 60 Load Case Properties and Parameters

Property

BuiltInParameter

Case Number

LOAD_CASE _NUMBER

Nature

LOAD_CASE_NATURE

Category

LOAD_CASE_CATEGORY

The LOAD_CASE_CATEGORY parameter returns an ElementId. The following table identifies the mapping between Category and ElementId Value.

Table 61: Load Case Category

Load Case Category

BuiltInCategory

Dead Loads

OST_LoadCasesDead

Live Loads

OST_LoadCasesLive

Wind Loads

OST_LoadCasesWind

Snow Loads

OST_LoadCasesSnow

Roof Live Loads

OST_LoadCasesRoofLive

Accidental Loads

OST_LoadCasesAccidental

Temperature Loads

OST_LoadCasesTemperature

Seismic Loads

OST_LoadCasesSeismic

The following Document creation methods create corresponding subclasses:

  • NewLoadUsage() creates LoadUsage
  • NewLoadNature() creates LoadNature
  • NewLoadCase() creates LoadCase
  • NewLoadCombination() creates LoadCombination.
  • NewPointLoad() creates PointLoad (an overload allows you to specify the load host element as a Reference). You can optionally specify a load type and sketch plane.
  • NewLineLoad() creates LineLoad (overloads allow you to specify the host element as a Reference or an Element). You can optionally specify a load type and sketch plane.
  • NewAreaLoad() creates AreaLoad (overloads allow you to specify the host element as a Reference or an Element). You can optionally specify a load type and sketch plane.

Because they are all Element subclasses, they can be deleted using Document.Delete().

Code Region 29-14: NewLoadCombination() 

public LoadCombination NewLoadCombination(string name,
        int typeInd, int stateInd, double[] factors, LoadCaseArray cases, LoadCombinationArraycombinations, LoadUsageArray usages);

For the NewLoadCombination() method, the factor size must be equal to or greater than the sum size of cases and combinations. For example,

  • If cases.Size is M, combinations.Size is N,
  • Factors.Size should not be less than M+N. The first M factors map to M cases in order, and the last N factors map to N combinations.
  • Check that LoadCombination does not include itself.

There is no Duplicate() method in the LoadCase and LoadNature classes. To implement this functionality, you must first create a new LoadCase (or LoadNature) object using the NewLoadCase() (or NewLoadNature()) method, and then copy the corresponding properties and parameters from an existing LoadCase (or LoadNature).

The following is a minimum sample code to demonstrate a creation of hosted point load in VB.NET:

Code Region 29-15: NewPointLoad() 


'' NewPointLoad with a host (in VB.NET)  

'' Select a beam, and get a curve of its analytical model.

Dim ref As Reference = rvtUIDoc.Selection.PickObject( _ 
    ObjectType.Element, "Select a beam")
Dim elem As Element = ref.Element
Dim aModel As AnalyticalModel = elem.GetAnalyticalModel
Dim aCurve As Curve = aModel.GetCurve

'' For simplicity, we assume we want to add a point load 
'' at the start point of the curve. 
 
Dim aSelector As New AnalyticalModelSelector(aCurve)
aSelector.CurveSelector = AnalyticalCurveSelector.StartPoint
Dim startPointRef As Reference = aModel.GetReference(aSelector)

'' Create a hosted point load
 
Dim force As XYZ = New XYZ(0.0, 0.0, -10000.0)
Dim moment As XYZ = New XYZ(-100.0, 100.0, 100.0)

Dim myPointLoad As PointLoad = _
    rvtDoc.Create.NewPointLoad( _ 
    startPointRef, force, moment, False, Nothing, Nothing)

Parent topic: Revit Structure