SoVolumeRender Node

[aman.sonu]

Hello Friends,

I m trying to change the number of slices of SoVolumeRender Node, but it is not showing any effect.



SoVolumeRender *volRend = new SoVolumeRender();

volRend->interpolation = SoVolumeRender::LINEAR;
volRend->composition = SoVolumeRender::ALPHA_BLENDING;
volRend->numSlicesControl.setValue(SoVolumeRender::AUTOMAT IC);

volRend->viewAlignedSlices.setValue(true);
volRend->numSlices = 1024;

I tried everything, but all in vain

Please help, if any one know the solution

Thanks in advance,
Aman

[mikeheck]

Originally Posted by aman.sonu

I m trying to change the number of slices of SoVolumeRender Node, but it is not showing any effect.

You're saying that you set different values in the numSlices field and there is no change in the image on the screen, right?
There are no known problems with this... You should be able to confirm that changing the number of slices works by running the VolRend demo/example that comes with the SDK. (On the VolumeRendering tab there is a slider to change the number of slices.)

What are the dimensions of the volume and what values of numSlices have you tried?

-Mike

[aman.sonu]

Thanks Mike.

Problem has solved. I am facing some new problems in Volume Rendering and very strange.

I have machine with following configuration:

Processor : Intel Xeon Quad Core 3.x 8 Cores (16 Threads)
Graphics Card: NVidea Quardro 4GB DDR3
RAM : 12GB DDR3

1.
I am converting DICOMs into Large Data Management, if I am loading DICOMs of *whole body* 2000 Dicoms. it shows artifacts and after clipped to half using ROI Manip.
it becomes clear/

What is this problem?

Is it hardware problem or Application problem?

2.

If i create more than 1 SoVolumeData nodes in the project, it starts showing artifacts?


Thanks in advance,

Aman

[mikeheck]

Hi Aman,

I don't know of any specific problem with either case you mentioned. But I'm also not sure what kind of "artifacts" you're seeing. Could you describe or post an image?

One kind of "artifact" you might see with a large data set like 2000 DICOM slices is incomplete refinement. As you know, when using LDM, VolumeViz starts by loading low resolution (subsampled) tiles of data, then progressively "refines" the image by loading higher resolution data until the full resolution data is displayed -- if possible. One reason it might NOT be possible to display the full resolution data for the whole volume is if the size of the data is larger than the system memory usage limit in VolumeViz. In version 8.0 and earlier, the default limit is only 256 megabytes. :-( If your DICOM slices are 512*512, then to load 2000 slices you need more than 512 megabytes.

If you are not currently setting the system memory limit, try adding this line after initializing VolumeViz:

// System memory VolumeViz is allowed to use (in MB)
SoLDMGlobalResourceParameters::setMaxMainMemory( 1000 );

You may want to look at some of the other limit settings available in this class (like texture memory). This will work better starting with version 8.1, because VolumeViz dynamically sets the default values based on the available resources.

-Mike

[aman.sonu]

Dear Mike,

Thanks for your prompt reply.

I have set default memory 4000MB already, it still show artifacts.

when i rotate the volume, the atrifacts reduce to minimal.

Please see the attached snap shot.

Regards,
Aman