Object Hierarchy | Related C++ Class: Cluster
Cluster
A cluster represents a set of components on a Geometry. For example, the
polygons of the left arm of a human model might be grouped together by creating a cluster.
A cluster has a SIObject.Type which corresponds to the component type that
it contains, (pnt, knot, poly). A geometry can have multiple clusters, including clusters of
different types. Any particular component might be included in multiple clusters. The
ClusterTypes that are supported on a geometry depend on the type of object.
For example only NurbsSurface or NurbsCurve can have a
siKnotCluster.
Clusters can be created on the geometry of a ParticleCloud. These clusters
are of type siVertexCluster but they contain Particles.
A cluster that includes all the components of a particular type is said to be "always complete",
which you can verify with the Cluster.IsAlwaysComplete method. An always-complete
cluster always covers all components of the geometry, even when components are added by a modeling
operation; however, notice that a cluster which covers all components of a geometry is not necessarily
always-complete. Other clusters may contain a subset of components. In all cases the indices of the
components in the cluster do not directly match the indices of the component on the geometry.
The mapping between cluster indices and geometry indices is available through
Cluster.Elements and Cluster.FindIndices.
Clusters are useful for storing per-component data with a ClusterProperty or
UserDataMap. Clusters can also have their own CustomProperty
objects. All these properties can be created with SceneItem.AddProperty and
enumerated with SceneItem.LocalProperties. Notice that some types of
ClusterProperty require the cluster to be always complete.
Warning: Operations that change the geometry, for example adding an edge to a mesh, can result
in the cluster growing or shrinking.
Note: As of v5.0, the base property SIObject.Parent called on a Cluster object returns
a Primitive instead of an X3DObject.
'
' This example shows how to create many different cluster types.
' It also shows how to find all clusters in a scene
'
NewScene ,false
set oRoot = Application.ActiveProject.ActiveScene.Root
set grid = oRoot.AddGeometry("Grid","MeshSurface")
set gridGeometry = grid.ActivePrimitive.Geometry
'Only certain types makes sense on a MeshSurface
'This cluster we will create as a subset of the vertices
gridGeometry.AddCluster siVertexCluster,"PntCluster",Array(1,4,7,10,13,16,19,22)
'The rest we will create as complete clusters
gridGeometry.AddCluster siPolygonCluster,"PolygonC"
gridGeometry.AddCluster siEdgeCluster
gridGeometry.AddCluster siSampledPointCluster
'A different set makes sense with Nurbs
set torus = oRoot.AddGeometry("Torus","NurbsSurface")
set torusGeometry = torus.ActivePrimitive.Geometry
torusGeometry.AddCluster siVertexCluster,"PntCluster"
torusGeometry.AddCluster siSampledPointCluster
torusGeometry.AddCluster siSurfaceCurveCluster
torusGeometry.AddCluster siKnotCurveUCluster
torusGeometry.AddCluster siKnotCurveVCluster
torusGeometry.AddCluster siBoundaryCluster
torusGeometry.AddCluster siKnotCluster
torusGeometry.AddCluster siTrimCurveCluster
torusGeometry.AddCluster siIsoLineUCluster
torusGeometry.AddCluster siIsoLineVCluster
torusGeometry.AddCluster siSubSurfaceCluster
set circle = oRoot.AddGeometry("Circle","NurbsCurve")
set circleGeometry = circle.ActivePrimitive.Geometry
circleGeometry.AddCluster siIsoPointCluster
circleGeometry.AddCluster siVertexCluster,"PntCluster"
circleGeometry.AddCluster siKnotCluster
set particleCloud = CreateParticleCloud().Item(0)
particleCloud.ActivePrimitive.Geometry.AddCluster siVertexCluster, "MyParticles"
' Now traverse the scene finding all the clusters
logmessage "Clusters in Scene......................"
set oSceneObjs = ActiveSceneRoot.FindChildren()
for each oItem in oSceneObjs
'Use error handling to skip over the objects that don't
'support clusters
on error resume next
set oClusters = oItem.ActivePrimitive.Geometry.Clusters
if ( err = 0 ) then
logmessage oItem & " has " & oClusters.Count & " Clusters: "
for each oCls in oClusters
logmessage " " & oCls & " (type: " & oCls.Type & ")"
next
end if
next
'The output of this script is:
'INFO : "Clusters in Scene......................"
'INFO : "grid has 4 Clusters: "
'INFO : " grid.polymsh.cls.PntCluster (type: pnt)"
'INFO : " grid.polymsh.cls.edge.clslist.Edge (type: edge)"
'INFO : " grid.polymsh.cls.PolygonC (type: poly)"
'INFO : " grid.polymsh.cls.sample.clslist.Sample (type: sample)"
'INFO : "torus has 11 Clusters: "
'INFO : " torus.surfmsh.cls.V_Knot_Curve (type: knotcrvv)"
'INFO : " torus.surfmsh.cls.U_Knot_Curve (type: knotcrvu)"
'INFO : " torus.surfmsh.cls.sample.clslist.Sample (type: sample)"
'INFO : " torus.surfmsh.cls.PntCluster (type: pnt)"
'INFO : " torus.surfmsh.cls.Surface_Curve (type: srfcrv)"
'INFO : " torus.surfmsh.cls.V_Isoline (type: isolinev)"
'INFO : " torus.surfmsh.cls.knot.clslist.Knot (type: knot)"
'INFO : " torus.surfmsh.cls.Boundary (type: bndry)"
'INFO : " torus.surfmsh.cls.Subsurface (type: subsrf)"
'INFO : " torus.surfmsh.cls.U_Isoline (type: isolineu)"
'INFO : " torus.surfmsh.cls.Trim_Curve (type: trimcrv)"
'INFO : "circle has 3 Clusters: "
'INFO : " circle.crvlist.cls.Isopoint (type: isopnt)"
'INFO : " circle.crvlist.cls.PntCluster (type: pnt)"
'INFO : " circle.crvlist.cls.knot.clslist.Knot (type: knot)"
'INFO : "cloud has 1 Clusters: "
'INFO : " cloud.cloud.cls.MyParticles (type: pnt)" |
//Step 1: Simulate the user creating a scene and selecting //some points on a grid var oGrid = ActiveSceneRoot.AddGeometry( "Grid", "MeshSurface" ) ; SelectObj( oGrid ) ; ActivateVertexSelTool(); AddToSelection( oGrid.Name + ".pnt[0-8]", null, true); //Step 2: Get the selected components using OM var oSubComponent = Selection(0).SubComponent ; //Expect that 9 components were selected logmessage( oSubComponent.ComponentCollection.Count ) ; //Step 3: it is simple to create a cluster var oCluster = oSubComponent.CreateCluster() ; logmessage( oCluster.FullName ) ; //Output of this example: //INFO : "9" //INFO : "grid.polymsh.cls.Point" |
