Floating Dialog Amnesty

Mar 16, 2010 by     9 Comments    Posted under: 3dsMax, DotNet, Maxscript, Tips and Tricks


Ack, not another one of those posts where the only picture is a p*ss poor dialog with some stolen twinkly twink icons. My old art teacher would be despairing right now, and perhaps comforting himself by grinding a yellow ochre paste. Oh, how he loved that yellow ochre.

A situation existed recently where between working on the train and at work, I’d lost some dialogs on the screen space outside the resolution of my laptop monitor. A few of 3ds max’s window locations are stored in the ini file.

inipath = getMAXIniFile()
setINISetting inipath “MtlEditorPosition”  “MainWindow” “0 0 375 734”
setINISetting inipath “RenderVFBPosition”  “Position” “0 0”
setINISetting inipath “MaterialBrowserDialogPosition” “Dimension” “0 0 340 600”
setINISetting inipath “EnvironmentDialogPosition” “Dimension” “0 0 350 580”
setINISetting inipath “RenderDialogPosition” “Dimension” “0 0 360 750”
setINISetting inipath “mentalrayMessagesPosition” “Dimension” “0 0 600 400”
setINISetting inipath “RenderPresetsCategoryDialogPosition” “RenderPresetsCategoryDialogDimension” “0 0 210 280”

But most of the useful ones are not – like the layer manager and curve editor.

Unfortunately, you cant set their position like you can a rollout floater – it meant it was time for the programmatic equivalent of James Herriot putting on a large rubber glove.

Windows has a wealth of useful functions in the API that aren’t yet exposed to the dotnet framework – well not out the box, there is a managed API but I haven’t looked into this yet . However this doesn’t mean you cant use native API calls in a managed code environment. You can declare an API call in a dotnet assembly, and with a little coercion, get it working as you want.

pinvokelogoThe place to look for Win32 and API related stuff is pinvoke.net. This has loads of info about how to call these windows functions via the managed dotnet framework

From the site itself-

“The term PInvoke is derived from the phrase “Platform Invoke”. PInvoke signatures are native method signatures, also known as Declare statements in VB”

After looking on this site, I found the methods i was looking for.

  • GetWindowRect – Gets the size of the window from the window handle
  • GetWindowPlacement – Gets the current window location from the window handle
  • MoveWindow – Moves the window to a screen location

All that was need now was to convert these signatures into a format string ready to compile directly from 3dsmax, so that I could call these win32 functions from a dotnetobject within 3dsmax, and hopefully retrieve my missing windows.

When you compile a dll directly in 3dsmax, you are taking the code that you would write within the Visual Studio window and sending it to the compiler manually. So the flavour of managed language you are using dictates the compiler type.

The key to this class is to set up some custom properties so that the data coming out when used in 3dsmax is not too weird –  it is logical to return a drawing.point for a location, and a drawing.size for a window size for instance.

Getwindowrect uses a RECT structure (a structure is similar to a class) but creating one in max can be tricky. Mike Biddlecombe on CG Talk had posted a method to instantiate a structure in 3dsmax by adding it into an array and retrieving the first member. That was brilliant stuff and typical of the sort of stuff that Mike is figuring out the whole time. I decided in this case, that since I was compiling an assembly anyway, i’d just handle all of the structure business there and avoid any potential banana skins. So I added a width and height property to the RECT structure definition, meaning after it was instantiated, you can call the method from PInvoke and return a structure that has standard properties. Planning return values in your classes is something that helps in the long run – It makes deployment much easier in Max. I have found that since the VS interface is easier to debug, it’s a good place to do as much as you can there.

fn DialogWindowOpsClass =
source = “”
source += “Imports System.Runtime.InteropServicesn”
source += “Imports System.Drawingn”
source += “Public Class DialogWindowOpsn”
source += “Public Structure RECTn”
source += “Public left As Integern”
source += “Public top As Integern”
source += “Public right As Integern”
source += “Public bottom As Integern”
source += “Public ReadOnly Property Width() As Integern”
source += “Getn”
source += “Return right – leftn”
source += “End Getn”
source += “End Propertyn”
source += “Public ReadOnly Property Height() As Integern”
source += “Getn”
source += “Return bottom – topn”
source += “End Getn”
source += “End Propertyn”
source += “End Structuren”
source += “Public Structure POINTAPIn”
source += “Public x As Integern”
source += “Public y As Integern”
source += “End Structuren”
source += “Public Structure WINDOWPLACEMENTn”
source += “Public Length As Integern”
source += “Public flags As Integern”
source += “Public showCmd As Integern”
source += “Public ptMinPosition As POINTAPIn”
source += “Public ptMaxPosition As POINTAPIn”
source += “Public rcNormalPosition As RECTn”
source += “End Structuren”
source += “<DllImport(“user32.dll”)> _n”
source += “Public Shared Function MoveWindow(ByVal hWnd As System.IntPtr, ByVal x As Integer, ByVal y As Integer, ByVal nWidth As Integer, ByVal nHeight As Integer, ByVal bRepaint As Boolean) As Booleann”
source += “End Functionn”
source += “<DllImport(“user32.dll”)> _n”
source += “Public Shared Function GetWindowRect(ByVal hWnd As System.IntPtr, ByRef lpRect As RECT) As Booleann”
source += “End Functionn”
source += “<DllImport(“user32.dll”)> _n”
source += “Public Shared Function GetWindowPlacement(ByVal hWnd As System.IntPtr, ByRef lpwndpl As WINDOWPLACEMENT) As Booleann”
source += “End Functionn”
source += “Public Function WindowSize(ByVal Hwnd As System.IntPtr) As System.Drawing.Sizen”
source += “Dim LPRECT As RECTn”
source += “GetWindowRect(Hwnd, LPRECT)n”
source += “Dim WinSize As System.drawing.size = New System.drawing.size(LPRECT.Width, LPRECT.Height)n”
source += “Return WinSizen”
source += “End Functionn”
source += “Public Function WindowPosition(ByVal Hwnd As System.IntPtr) As System.Drawing.Pointn”
source += “Dim intRet As Integern”
source += “wpTemp.Length = System.Runtime.InteropServices.Marshal.SizeOf(wpTemp)n”
source += “intRet = GetWindowPlacement(Hwnd, wpTemp)n”
source += “Dim WinPoint As System.drawing.point = New System.drawing.point(wpTemp.rcNormalPosition.left, wpTemp.rcNormalPosition.top)n”
source += “Return WinPointn”
source += “End Functionn”
source += “End Class”

VBProvider = dotnetobject “Microsoft.VisualBasic.VBCodeProvider”
compilerParams = dotnetobject “System.CodeDom.Compiler.CompilerParameters”
compilerParams.ReferencedAssemblies.add “C:WindowsMicrosoft.NETFrameworkv2.0.50727System.drawing.dll”
compilerParams.GenerateInMemory = on
compilerResults = VBProvider.CompileAssemblyFromSource compilerParams #(source)

— this is very useful to debug your source code and check for referencing errors
if (compilerResults.Errors.Count > 0 ) then
errs = stringstream “”
for i = 0 to (compilerResults.Errors.Count-1) do
err = compilerResults.Errors.Item[i]
format “Error:% Line:% Column:% %n” err.ErrorNumber err.Line
err.Column err.ErrorText to:errs
MessageBox (errs as string) title: “Errors encountered while compiling VB code”
return undefined
return compilerResults.CompiledAssembly.CreateInstance “DialogWindowOps”

What this code does is make a class that can be instantiated in max and used to control the positions of the dialogs in the 3dsmax user interface, whether we can see them or not.

In order to call them though, we need an array of handles for the active max dialogs. Fortunately, Maxscript gives us a way of doing this –


The rest, was building an interface. I went for the datagridview – Its a complex user control and I am probably only scratching the surface of the sort of things you can do. Its designed for handling masses of complex data from data sources like sql databases but you can just use it like a listview. Its just got a few more options.

Maxscript also has methods for interacting with win32 functions, so it’s entirely possible that this could be achieved using that, but then that’d just be cheating, wouldn’t it?