[vtkusers] Volume Rendering Performance With Two Volumes

[ianl]

Just to be clear, I am interacting with each volume in turn for a few seconds
each. It appears that one of the volumes gets cached onto the card and is
performant, but not the other, no matter how much I interact with it.

I have done some more experimentation, and down sampling the volumes makes a
significant improvement to performance. This seems to imply some swapping
on/off is going on. Incidentally, GPU-Z shows plenty of GPU RAM left
(~700MB), but I don't know how accurate this is and of course it does not
give me any idea how fragmented it is.

Am I correct in assuming that once the volume data texture is loaded into
GPU memory, then performance should only depend on
ImageSampleDistance/viewport size i.e. the number of rays cast and
SampleDistance i.e. the sample spacing - (in mm?) along the ray? Having less
data at a wider spacing to sample through should not make a difference to
performance, only quality - or is this a gross simplification.

Thanks,
Ian



--
Sent from: http://vtk.1045678.n5.nabble.com/VTK-Users-f1224199.html