This simple example shows how to pass in the vertex and polygon data in Python.

Application.CreatePrim("Cube", "MeshSurface", "", "")
oCube = Application.Selection(0)

# tuple of tuples
# one tuple for the X coordinate, one for the Y, and one for the Z
verts = ((-0.5, 0.5, -0.5, 0.5, -0.5, 0.5, -0.5, 5.0), (-0.5, -0.5, 0.5, 0.5, -0.5, -0.5, 0.5, 0.0), (-0.5, -0.5, -0.5, -0.5, 0.5, 0.5, 0.5, -18.0))

# tuple of polygon data
polys = (4, 0, 2, 3, 1, 4, 0, 1, 5, 4, 4, 0, 4, 6, 2, 4, 1, 3, 7, 5, 4, 2, 6, 7, 3, 4, 4, 5, 7, 6)

Application.FreezeObj(oCube)

oCube.ActivePrimitive.Geometry.Set(verts,polys)

To help understand the vertex and polyon data, consider this simple polygon mesh:

Given the above polygon mesh, this snippet:

oCube = Application.Selection(0)

data = oCube.ActivePrimitive.Geometry.Get2()
verts = data[0]
polys = data[1]

print verts
print polys

would print this:

#  ((-3.0, 4.0, 1.0, -2.0), (0.0, -4.0, 0.0, 0.0), (1.0, -4.0, 5.0, 3.0))
# (4, 0, 1, 2, 3)

The context for custom menu callbacks gives you access to the current view instance, so you can use the selection view attribute to get the selected ICE nodes. See line 35 in the example.

import win32com.client
from win32com.client import constants

null = None
false = 0
true = 1

def XSILoadPlugin( in_reg ):
	in_reg.Author = "blairs"
	in_reg.Name = "My_ICETreeUserTool_Plugin"
	in_reg.Major = 1
	in_reg.Minor = 0

	in_reg.RegisterMenu(constants.siMenuICEViewToolsID,"My_ICETreeUserTool_Menu",false,false)
	#RegistrationInsertionPoint - do not remove this line

	return true

def XSIUnloadPlugin( in_reg ):
	strPluginName = in_reg.Name
	Application.LogMessage(str(strPluginName) + str(" has been unloaded."),constants.siVerbose)
	return true

def My_ICETreeUserTool_Menu_Init( in_ctxt ):
	oMenu = in_ctxt.Source
	oMenu.AddCallbackItem("My ICE Tree User Tool","OnMyICETreeUserTool")
	return true

def OnMyICETreeUserTool( in_ctxt ):
	itv = in_ctxt.GetAttribute("Target")
	
	LogMessage( 'View: ' + itv.Name )
	
	# get the selected nodes
	nodes = itv.GetAttributeValue('selection')
	LogMessage( 'Selected nodes: ' + nodes )
		

I was recently asked whether it’s possible to find docked FxTree views and figure out 1) what specific tree is loaded, and 2) what nodes are selected in the Fx tree.

You can find docked Fx Tree views, but unfortunately there’s no way to find out what’s in that view.
Here’s a Python snippet that finds docked Fx Tree views:

# Find docked Fx Tree views
oVM = Application.Desktop.ActiveLayout.Views.Filter( "View Manager" )
oFxTreeViews = oVM(0).Views.Filter( "Fx Tree" )

for view in oFxTreeViews:
    Application.LogMessage(view.Name+": "+view.Type)

In the XSI SDK, you use attributes to access the contents of a view, and there are no attributes defined for Fx Tree views.

For example, here’s how it works for an ICE Tree view:

# Find docked ICE Tree views
oVM = Application.Desktop.ActiveLayout.Views.Filter( "View Manager" )
oICETreeViews = oVM(0).Views.Filter( "ICE Tree" )

# Get the ICE tree that is loaded into the view
Application.LogMessage( oICETreeViews(0).GetAttributeValue( "container" ) );

# Get the selected nodes in the ICE tree
Application.LogMessage( oICETreeViews(0).GetAttributeValue( "selection" ) );

Technically, I suppose this is not really a gotcha. But for someone like me who has to switch between scripting languages frequently, it’s a potential “gotcha”.

In Python, functions and methods are legitimate objects. That’s why you can do this:

App = Application
LogMsg = App.LogMessage
ClassName = App.ClassName

but sometimes you might forget the parentheses after a name, and unlike JScript, you won’t get a syntax error (at least not for the missing parentheses). For example, this little snippet will give you a “# AttributeError: ‘NoneType’ object has no attribute ‘AddKey'” error:

param = Application.Dictionary.GetObject( "null.kine.local.rotx" )

if str(param.Source) == 'None':
    param.AddFcurve
    fcurve = param.Source
    fcurve.AddKey( 10, 90 )
    fcurve.AddKey( 20, 45 )

In JScript, you’d get a syntax error for the missing parentheses. I’m not saying that that is better 😉 it’s just a difference you have to be aware of.

param = Dictionary.GetObject( "null.kine.local.rotx" )
param.AddFcurve
// ERROR : Object doesn't support this property or method - [line 3]

Some related links:

• When Pythons Attack (Common Mistakes of Python Programmers)
• Python Conquers The Universe Gotcha — forgetting parentheses