[slicer-users] Dual Volume - Volume Rendering

Yanling Liu vrnova at gmail.com
Tue Jun 1 19:18:44 EDT 2010

Hello Kumar,

It is interesting that you are using CT and PET volumes with different size
and spacing. The multi-volume module is currently under development and the
initial goal was to compare pre and post treatment images. You could imagine
in this case both bg and fg images will have same spacing, size, etc. While
I am excited for the new requirement to handle images with different
modality, size, and spacing, I'll need some time to do coding. Some screen
shots will also help me to better understand it. At the meanwhile, you may
able to render images if you can do some padding and resampling to PET

Are you able to provide me some sample CT/PET dataset pair so I can test
multi-volume module in development?


From: Devakumar Devadhas [Devakumar.Devadhas at jefferson.edu]
Sent: Tuesday, June 01, 2010 3:22 PM
To: Liu, Yanling (NIH/NCI) [C]; Devakumar.Devadhas at jefferson.edu;
alexy at bwh.harvard.edu
Subject: RE: Dual Volume - Volume Rendering


Thanks for your response. The technique I used is Composite with Shading. I
have tried all other techniques which you have provided.

Multi-Volume GPU Ray casting doesn't have Depth peeling option. I have tried
Bg/Fg Ratio. The size of the CT dataset is 512x 512 x 431. The size of the
PET dataset is 128 x 128 x 344. I tried with the same size assuming that
your GPU ray casting module may resample the data to half the size. I
resampled the data and tried also. Neither worked. Ofcourse image spacing is
not same in both datasets. It may be very hard to have same image spacing
unless both are CT datasets and acquired in the same machine. I have the
latest NVIDIA drivers installed in the system.



Hello Kumar,

Could you please provide me more details for the problem? I would like to
know which techniques you have selected for bg and fg channel. Did you
change parameters such as distance color blending or volumetric depth
peeling? What is the size of your data set? Do bg and fg volumes have same
origin, size and spacing? For now the multi-volume rendering mapper is still
under development and won't handle bg and fg volumes with different size,
spacing and/or origin.

Also please make sure the latest Nvidia driver is correctly installed in
your system.

On Mon, May 31, 2010 at 8:47 PM, Devakumar Devadhas <
Devakumar.Devadhas at jefferson.edu> wrote:

> Hi
> Volume Rendering with Single volume of data works fine. But with dual
> volume, the algorithm "NCI GPU Ray Casting (Multi-Volume) doesn't work. I
> have tried in two systems.
> System 1:
> Slicer 3.6 RC1 (Slicer 3 3.5.2010-05-09) Stable Release
> Windows XP 32 bit
> GeForce GTX 285 (1GB video memory)
> 4GB of RAM
> Problem: Severe artifact in rendered image (not able to recognize the
> image)
> System 2:
> Slicer 3 3.5.2010-05-17 Snapshot
> Windows XP 64 bit system
> Quadro FX 5800 card (4GB video memory) and  also.
> 48GB RAM
> Problem: 3D Display window is not updated. Ray casting is done
> indefinitely.
> I have tried with todays nightly build and last two days of nightly build
> also. I cannot use CPU ray casting as it supports only one volume.
> Appreciate your help.
> Thanks
> Kumar
> ----------------------------------------
> Devakumar Devadhas, Ph.D
> Postdoc Fellow
> Department of Radiology and Molecular Biology
> Thomas Jefferson University
> Philadelphia
> PA-19107
> _______________________________________________
> slicer-users mailing list
> slicer-users at bwh.harvard.edu
> http://massmail.spl.harvard.edu/mailman/listinfo/slicer-users
> To unsubscribe: send email to
> slicer-users-request at massmail.spl.harvard.edu with unsubscribe as the
> subject
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://massmail.spl.harvard.edu/pipermail/slicer-users/attachments/20100601/20cd9971/attachment.html>

More information about the slicer-users mailing list