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Operator

Object Hierarchy | Related C++ Class: Operator

Inheritance

SIObject
  ProjectItem
    Operator

Introduced

1.5

Description

The Operator object represents an operator in the scene graph. Objects or Parameters are connected to the operator via InputPorts or OutputPorts, which may be organized into PortGroups. SDK users can create their own operators, which are represented in the Object Model as CustomOperators.

The responsibility of an operator is to change the output object (or objects) with the result of some algorithm. The only data the operator can read from the scene is via its input ports and parameters. For example, a typical operator might change the position of one object (the output) based on the position of several other objects (the inputs). The same object may act as both the input and the output of an operator, for example a typical deformation operator will read a geometry and output a modified version of the point positions of that same geometry. Selecting an operator in the "SDK Explorer" view is a good way to learn more about its ports and parameters.

To access individual ports from within the evaluation of a Self-Installed Custom Operator use the OperatorContext object. From outside the evaluation callback use the Operator.PortAt method.

Almost all Operators expose one or more Parameters which control the behavior of the operator. For example, the "subdivu" and "subdivv" parameters on a polygon mesh geometry operator control the number of polygons that a polygon mesh is generated with.

The most common way to create and connect a built-in operator is by calling the ApplyOp command. However, there are many specialized commands for creating operators, for example ApplyTopoOp, ApplyHairOp and ApplyGenOp. Operators are also often created indirectly, for example calling X3DObject.AddGeometry creates an operator that generates the geometry.

Methods

Properties

Examples

JScript Example

/*
   This example illustrates how to generate a mesh by using the loft operator and
   a number of input curves. The code also illustrates how to traverse the operator's
   port group, port group instances and ports and logs the name of the port, its type
   and the full path name of the object connected to the port.
*/
NewScene( null, false );

var arc = ActiveSceneRoot.AddGeometry( "Arc", "NurbsCurve" );

// Duplicate arc 4 times and translate in y
var args = new Array(19);
args[0] = arc;                                       // source object
args[1] = 4;                                         // number of copies
args[9] = siApplyRepeatXForm;                        // Xform
args[18] = 1;                                        // Ty

var objs = Application.ExecuteScriptCommand( "Duplicate", args );

// Create array containing arc and duplicates
var aobjs = new Array(5)
aobjs[0] = arc;
for ( var i = 0; i < objs.count; i++ ) aobjs[i+1] = objs(i);

// Apply loft operator
var op = ApplyOp( "Loft", aobjs )(0);

// Traverse port group, instances and ports and log port connections

// For each port group ...
for ( var idxGroup = 0; idxGroup < op.GetNumPortGroups(); idxGroup++ )
{
   // For each instance in a port group ...
   for ( var idxInstance = 0; idxInstance < op.GetNumInstancesInGroup( idxGroup ); idxInstance++ )
   {
       // For each port in a  port group instance ...
       for ( var idxPort = 0; idxPort < op.GetNumPortsInGroup( idxGroup ); idxPort++ )
       {
          // Get a specific port
          var port = op.PortAt( idxPort, idxGroup, idxInstance );

          // If the port is an input port ...
          if ( port.PortType == siPortInput )
              porttypestr = "input"
          else if ( port.PortType == siPortOutput )
              porttypestr = "output"
          else
              porttypestr = "error"

          var target = port.Target2;

          // ... and the connected type is an object connection
          if ( typeof(target) == "object" )
          {
              Application.LogMessage( op.Name + " group:" + port.GroupIndex + " " + " instance:" + port.GroupInstance 
                            + " " + porttypestr + "port:" + port.Index + ":" + target.FullName );
          }
       } 
   }
}

// Expected results:
//INFO : "Loft group:0  instance:0 inputport:0:arc.crvlist"
//INFO : "Loft group:0  instance:0 inputport:1:arc.kine.global"
//INFO : "Loft group:0  instance:1 inputport:0:arc1.crvlist"
//INFO : "Loft group:0  instance:1 inputport:1:arc1.kine.global"
//INFO : "Loft group:0  instance:2 inputport:0:arc2.crvlist"
//INFO : "Loft group:0  instance:2 inputport:1:arc2.kine.global"
//INFO : "Loft group:0  instance:3 inputport:0:arc3.crvlist"
//INFO : "Loft group:0  instance:3 inputport:1:arc3.kine.global"
//INFO : "Loft group:0  instance:4 inputport:0:arc4.crvlist"
//INFO : "Loft group:0  instance:4 inputport:1:arc4.kine.global"
//INFO : "Loft group:1  instance:0 inputport:0:surfmsh.kine.global"
//INFO : "Loft group:1  instance:0 outputport:1:surfmsh.surfmsh"

See Also

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