What Happens when the Function Already Returns a Value?

Some Softimage functions return both output arguments and return values. If the function has a return value explicitly defined, you cannot extract any output arguments via the ISIVTCollection because the function is returning an a specific value instead.

Tip

You can check the Return Value section in the Commands and Scripting Reference to see whether it uses an explicit return value and what that value is.

In these cases, VBScript must pass output parameters in order to retrieve the information via output arguments but for JScript, and Python, other strategies must be considered.

Strategies and Workarounds

In most cases, there are special versions of those functions that use output arguments and return values. These functions generally have the same name as the output argument versions, but with '2' appended to the name. For example, the NurbsSurface.GetTrim function allows output arguments (see VBScript Example: Getting Output Arguments from a Method), but the NurbsSurface.GetTrim2 function returns an array of output values (JScript Example: Using the Method Ô2' Workaround).

Custom Command Workaround

If there is no alternate (compliant) version of the function, your only option for a workaround is to create a VBScript custom command to call the non-compliant command and return an array containing both the output arguments and return value.

VBScript Example: Define the Work around Command

Note that this snippet contains the Execute callback for the custom command. See Example: Custom Command Workaround for Both Output Arguments and Return Values for the full implementation of this plug-in.

' Execute callback for the custom command
function MyGetSkeleton_Execute( InputObj )
	' Call the GetSkeleton command and pack the output 
	' argument and the return value in an array 
	set oSkel = GetSkeleton( InputObj, lIndex )
	aReturn = Array( lIndex, oSkel )

	' Return the array
	MyGetSkeleton_Execute = aReturn 
end function

JScript Example: Call the Work around Command

' Execute callback for the custom command
function MyGetSkeleton_Execute( InputObj )
	' Call the GetSkeleton command and pack the output 
	' argument and the return value in an array 
	set oSkel = GetSkeleton( InputObj, lIndex )
	aReturn = Array( lIndex, oSkel )

	' Return the array
	MyGetSkeleton_Execute = aReturn 
end function

JScript Example: Call the Work around Command

NewScene( null, false );

Create2DSkeleton( -3.004, 2.152, 0.000, -1.531, -1.163, 0.000, 0.000, 0.000, 1.000, 1 );
AppendBone( "eff", 0.853, 1.396, 0.000 );
AppendBone( "eff", 2.578, -1.532, 0.000 );

// Returns a VBArray, which must be converted to a JS Array
var RtnArray = MyGetSkeleton( "bone1" ).toArray();

// The output argument is the first item (a Long)
var MyObjIndex = RtnArray[0];
LogMessage( "Index of objects in skeleton: " + MyObjIndex );

// The return value is the second item (XSICollection)
var MySkeleton = RtnArray[1];
for ( i=0; i<MySkeleton.Count; i++ ) {
	LogMessage( "Item[" + i + "] = " + MySkeleton(i) );
}

// So both are available now in JScript
// INFO : Index of objects in skeleton: 2
// INFO : Item[0] = root
// INFO : Item[1] = bone
// INFO : Item[2] = bone1
// INFO : Item[3] = bone2
// INFO : Item[4] = eff

Except where otherwise noted, this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License