Softimage SDK Programmer's Guide > Working with the SDK > Modeling >

# Enumerating Polygon Islands

This example demonstrates how to enumerate polygon islands by implementing a function that returns an array of all the polygon islands, each one as a PolygonFaceCollection.

## JScript Example: enumerating polygon islands

    function GetIslands(in_obj)
    {
    	var arrIslands = new Array();
    	var plyPolygons = in_obj.ActivePrimitive.Geometry.Polygons;
    	var arrSeen = new Array(plyPolygons.Count);					// for optimization

    	for ( var i=0; i<plyPolygons.Count; i++ ) {
    		// Skip any we've already seen
    		if ( arrSeen[i] ) { continue; }

    		// Stuff the current polygon into an XSICollection (custom
    		// filters only accept and return XSICollections)
    		var xsiCurrPolygons = new ActiveXObject("XSI.Collection");
    		xsiCurrPolygons.Add(plyPolygons(i));

    		// Activate and apply the filter
    		var fltPolyIslandFilter = Application.Filters("Polygon_Island");
    		var xsiCurrIslands = fltPolyIslandFilter.Subset(xsiCurrPolygons);

    		// To return an actual PolygonFaceCollection instead of an
    		// XSICollection, we can convert it via the SubComponent
    		var plyCurrIslands = Dictionary.GetObject(xsiCurrIslands).SubComponent.ComponentCollection;

    		// Indicate that we've see all of these components (optimization)
    		for ( var j=0; j<plyCurrIslands.Count; j++ ) {
    			arrSeen[plyCurrIslands(j).Index] = 1;
    		}

    		// Add the PolygonFaceCollection of polygon islands to the return array
    		arrIslands.push(plyCurrIslands);
    	}

    	return arrIslands;
    }

    // Open the club bot sample scene and select the feet polygon mesh
    var strClubBot = XSIUtils.BuildPath(
    	Application.InstallationPath(siFactoryPath),
    	"Data", "XSI_SAMPLES", "Scenes", "club_bot.scn"
    );
    OpenScene(strClubBot, false);
    SelectObj("club_bot.BotFeet");

    // Using this in a tool, you might use the selection:
    var e = new Enumerator(Selection);
    for ( ; !e.atEnd(); e.moveNext() ) {
    	var obj = e.item();
    	var arrPolyIslands = GetIslands(obj);
    	Application.LogMessage( "# of polygon islands: " + arrPolyIslands.length );
    }

    // Expected results:
    // INFO : # of arrPolyIslands: 2