[vtkusers] Help : how memory is used with VTK ?

[Nicolas Cathaud]

Hi Amy,

Thank you for your answer !

What I want to do it's to manage a scene with a lot of actors, and if I
don't free memory when I hide an actor, it can be a big problem. Indeed, I
will have a lot of memory reserved but don't used. The only way I find to
free this memory is closing the vtkRenderWindow, which is not a great
solution... If I remove the actor or if I delete it, the memory is not
freed.

I don't mind if I need to re-read data or re-execute filters.

Moreover, I notice that the memory is freed if I delete the vtkRenderWindow,
and if I re-open it there are no compute, the display is immediate. So I
don't understand why there's a lot of memory used even if my actor is hide.
Can you explain that ?

Regards

Nicolas Cathaud

2006/4/27, Amy Squillacote <amy.squillacote at kitware.com>:
>
> Hi Nicolas,
>
> Assuming that you're saying you see a memory increase just before VTK
> first renders your model, then the reason is VTK's demand-driven
> pipeline.  VTK does not read data, run filters, etc. until something
> tells it to (rendering, in your case).
>
> This should also explain why the memory isn't freed when you hide
> part of your scene; memory was allocated when these parts of your
> scene were first rendered, and if the memory was freed just because
> you weren't rendering that part of the scene, then data would have to
> be re-read, filters re-executed, etc. when you wanted to render that
> part of the scene again.
>
> - Amy
>
> At 11:31 AM 4/27/2006, Nicolas Cathaud wrote:
> >Hello everybody,
> >
> >I have many questions about vtk and memory. When I load a big model with
> VTK
> >(nearly 300.000 triangles), I notice that the memory clearly increases
> just
> >before display. I just want to know if it's possible to avoid this, even
> if
> >I lose in movement's fluidity. I can't find what consume this memory, and
> >I'm curious to know the reason of that. Is it an openGL mode which
> allocate
> >a lot of memory in order to increase the performance ? Is it the data
> >structure of vtk ?
> >
> >My second question is how to free this memory when I want to hide an
> element
> >of the scene. Indeed, I have many actors in my scene, and I want to have
> the
> >possibility to hide or show this actors, so I use the commands "AddActor"
> >and "RemoveActor", but it didn't free the memory when there are no actor
> in
> >the scene.
> >
> >Thank you for reading this message.
> >
> >Regards.
> >
> >Nicolas CATHAUD
> >
> >
> >
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