[vtkusers] vtkGPUVolumeRayCastMapper: Updateing ImageData after first Rendering?

Aashish Chaudhary aashish.chaudhary at kitware.com
Mon Feb 20 10:27:10 EST 2017

Hi Willy,

The first call is done to get the min/max for transfer functions (without
looking into code). I do not remember if your data is changing, if it does
it will trigger min/max computation. Are you providing your own transfer

- Aashish

On Mon, Feb 20, 2017 at 7:59 AM Willy <Wiggerl at linhuber.info> wrote:

> I found a bit information about the 1m 29 s wait time. The first call of
> vtkOpenGLGPUVolumeRayCastMapper::GPURender calls
> vtkVolumeTexture::LoadVolume and that calls vtkDataArray::GetRange and that
> method loops through my 3GB scalar data and calls each time min and max (to
> get the min and max value of all values). Can i prevent vtk from doing
> that?
> Why does vtk even calculate that? Does vtk maybe want to scale the
> greyvalues bewenn min and max? Maybe i can disable that somehow?
> Moreover i tested a application named ParaView (ParaView uses vtk too).
> ParaView does not wait 1m29s. It seems like it is not neccessary to
> calculate min and max.
> --
> View this message in context:
> http://vtk.1045678.n5.nabble.com/vtkGPUVolumeRayCastMapper-Updateing-ImageData-after-first-Rendering-tp5742153p5742247.html
> Sent from the VTK - Users mailing list archive at Nabble.com.
> _______________________________________________
> Powered by www.kitware.com
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
> Please keep messages on-topic and check the VTK FAQ at:
> http://www.vtk.org/Wiki/VTK_FAQ
> Search the list archives at: http://markmail.org/search/?q=vtkusers
> Follow this link to subscribe/unsubscribe:
> http://public.kitware.com/mailman/listinfo/vtkusers
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/vtkusers/attachments/20170220/dc049cb1/attachment.html>

More information about the vtkusers mailing list