instance

    device = new IrrlichtDevice(drivertype,
                                        optimalmode.Resolution,
                                        optimalmode.Depth, fullscreen,
                                        true, //Stencil Buffer (for shadow)
                                        false, //Vertical Synchronisation (use it if you want your application not to go over 70 FPS)
                                        false, //Anti Aliasing
                                        this.myDeviceHDLE); //

def

   IntPtr myDeviceHDLE;
   IrrlichtDevice device;

   myDeviceHDLE = this.panel1.Handle;

irr tourne dans un thread different du document.

voilà, tout me parrait normal...