[vtkusers] execution pipeline

[Marcelo Ruetalo]

Thanks for your reply, Matk. I found the problem last night, and it was, 
indeed, the pointer to class vs class issue...

Marcelo

> > I define a class with, say (to make it simple)
> > - a vtkRenderer, a vtkRenderWindow, a vtkActor as data members
> > - constructor to initialize things and render the actor in some simple 
> > way
> 
> Please be a bit more precise. I hope you don't use vtk classes on 
> stack, but keep pointers to them (and do proper Reference counting 
). 
> Do you have some code snippets, preferably of the constructor?
> 
> > When I create an instance of the class, everything is fine and rendered
> > like I want, but when I call the public method nothing changes! Do I
> > have to somehow explicitly tell VTK to update the actors in the
> > renderer?
> 
> An update occurs every time someone kicks it off and propagates only 
> upwards. This means, if no-one calls an Update(), nothing will change 
> on your screen. But typically, there's an instance of 
> vtkRenderWindowInteractor living in your application and if you click 
> into your rendering window to pan, zoom or rotate, it will start an 
> Update() from the very end of the rendering pipeline.
> 
> If you want to update the screen yourself, try calling Render() on your 
> vtkRenderWindow() or vtkRenderer() instance.
> 
> I hope this helps,
> 
> Mark
> 
> 
>