Hello Al, Hello James,

please test the following code for the shell command:

    // Shell
function Shell()
{
	this.addInput("Surfaces","objectlist");
    this.addInput("Thickness","numarray");
    
	this.addOutput("Out","objectlist");
    
    this.properties = { mode:["Long","Long","Short"], thickness:[1], direction:["Normal","Normal","Flip","Centerline"] };
    
}

Shell.title = "Shell";
Shell.desc = "Shell";

Shell.prototype.onExecute = function()
{
    var surfaces = this.getInputData(0, moi.geometryDatabase.createObjectList());
    
	var data = this.processInOut(this.properties.mode[0], this.multiProcess, null, this.properties.thickness);

	this.properties.thickness = data.inputs[1];
	this.setOutputData(0, data.outputs[0]);
}

Shell.prototype.multiProcess = function(s, t) 
{	
	return [factory('shell', s, t, this.properties.direction[0])];
}

LiteGraph.registerNodeType("Construct2/Shell", Shell);

@James: Please test the code first, correct the construct2.js file and post/replace it. The problem was, that you had a look in the sometimes outdated API-Documentation - it's always a good idea to look also in Michaels code under the command folder.

A nice day to all
Karsten